Methods for isolating compounds

ABSTRACT

The present invention in its broadest aspect relates to a method for reducing glycoalkaloid content and turbidity of an aqueous phase comprising compounds selected from two or more of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid and phenolic compounds of which at least one compound is selected from PA, PI, LipO and PPO; a) providing an aqueous phase comprising compounds selected from two or more of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid and phenolic compounds of which at least one compound is selected from PA, PI, LipO and PPO; and b) performing one or more steps to reduce the concentration of solanine in the dry matter of the aqueous phase with at least 15 percent, such as at least 20% such as at least 25% and to achieve an optical density at 620 nm of the remaining aqueous phase of less than 0.7; such as less than 0.5; such as less than 0.3; such as less than 0.2 such as less than 0.1 and thereby obtaining an aqueous phase having reduced glycoalkaloid content and turbidity compared to an untreated aqueous phase.

CROSS REFERENCE TO RELATED APPLICATIONS AND INCORPORATION BY REFERENCE

This application is a U.S. National Stage of International ApplicationNo. PCT/DK2017/050365, filed Nov. 7, 2017, which claims the benefit ofDanish Patent Application No. 2016 70871, filed Nov. 7, 2016, DanishPatent Application No. 2017 70532, filed Jun. 30, 2017, Danish PatentApplication No. 2017 70611, filed Aug. 11, 2017, and Danish PatentApplication No. 2017 70677, filed Sep. 11, 2017.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to methods for isolating compounds,particularly proteins, from materials containing such compounds,particularly plant materials, to the isolated compounds, to compositionscomprising the isolated compounds and to use and application of theisolated compounds.

BACKGROUND OF THE INVENTION

Compounds such as proteins and metabolites comprised in plants arevaluable and useful in many different applications such as nutrition,medical treatments, cosmetics and acceptable process aids for industrialmanufacture of the same. Particularly, such proteins and metabolites insignificant crop plants, such as potatoes, are interesting and becomeeven more valuable and useful in isolated form. Potatoes, for example,contain useful patatins and protease inhibitors which are desirable touse in isolated and more pure forms.

Kong et al. (Recovering proteins from potato juice by complexation withnatural polyelectrolytes; International Journal of Food Science andTechnology 2015, 50, 2160-2167) relates to characterization of potatoproteins and their protein-polyelectrolyte complexes.

Waglay & Karboune (Potato Proteins: Functional Food Ingredients; Chapter4; Advances in Potato Chemistry and Technology, 08 2016) disclose potatoproteins prepared by various methods including thermal coagulation,acidic precipitation, precipitation with salt, ethanol, ammonium sulfateor CMC, anion-exchange chromatography or size exclusion separation.

Gerrit A Van Köningsveld (Journal of the Science of Food andAgriculture, vol 82, pp 134-142, 2001) disclose the solubility of potatoproteins as influenced by pH and various additives.

However, many plants, including potatoes, also contain compounds thatare undesirable or even poisonous in some applications. Particularly,potatoes (belonging to the night shade family) contain several compoundswhich are undesired for some applications, while useful in otherapplications. Patatins and protease inhibitors are useful in nutritionand nutraceutical application, while glycoalkaloids (toxic),lipoxygenase (rancidify fats/oils), polyphenol oxidase (oxidizes andtans food stuff) or phenolic compounds are not desired in nutrition andnutraceutical applications. On the other hand, isolated glycoalkaloidsare useful in certain cosmetic or pharmaceutical applications.Accordingly, there is a need for methods for separating and/or isolatingfunctional plant compounds to be used in industrial applications.

Isolation of highly purified proteins from plant extracts is a demandingtask due to the extremely complex and reactive compositions achievedwhen the plant tissue is mechanically and/or chemically disrupted.Highly selective separation methods, such as adsorption chromatography,may relatively straightforward be applied to specifically adsorb andrelease the proteins free from contaminants but such methods have proventoo costly in many applications targeting proteins for e.g. foodapplications. Other methods, like membrane filtration and classicalseparation of proteins by isoelectric precipitation or precipitation bythe use of lyotropic salts (salting put) and organic solvents, haveproven to be too unspecific when applied to crude plant extracts.

The increasing need for sustainable production of food and feedmaterials further emphasize the complexity involved in designingindustrial scale processing methods that preserves the value of anygiven raw material and the product and side streams resulting fromprocessing it. This means an increased need to avoid product losses andto avoid processing methods that destroy the value of the othercomponents in the raw material such that they may be worked up asvaluable products too and thereby increase the sustainability of theentire value chain. This is in contrast to many prior art processes thatmay focus mainly on one product to be produced from the raw material andwhere the potential value of side streams is neglected.

US 2003/0077265 discloses a method to produce potato protease inhibitorscomprising extracting potatoes with aqueous organic acids and saltscombined with heat denaturation and removal of undesired proteinsfollowed by ultrafiltration to concentrate and diafiltrate the proteaseinhibitors. However, this method cannot be applied to the potato fruitjuice being produced as a large volume side stream during themanufacture of potato starch. Further this method destroys the value ofthe major part of the potato by the use of e.g. formic acid, salts andheating directly to the potatoes.

Especially in the field of potato protein isolation there has for manyyears been attempted many different techniques to economically producefood grade proteins out of the fruit juice released during theproduction of potato starches. It has, however, been difficult toachieve the quality needed for food proteins while at the same timeapplying an industrially applicable, robust and profitable processingscheme. For example, according to several scientific reports (e.g.Straetkvern K O & Schwarz J G (2012) Recovery of Native Potato ProteinComparing Expanded Bed Adsorption and Ultrafiltration. Food andBioprocess Technology. 5(5), 1939-1949 and Zwijnenberg H J, Kemperman AJ B, Boerrigter M E, Lotz M, Dijksterhuis J F, Poulsen P E & Koops G H(2002) Native protein recovery from potato fruit juice byultrafiltration. Desalination. 144(1-3), 331-334) ultrafiltration haslow selectivity and only poorly separate polyphenols and brownpolyphenol complexes from proteins thus giving a powder with a finalbrown hue and higher content of chlorogenic acids, and in addition it isoften encountered with membrane concentration of potato fruit juice thatfouling of the membranes lead to low flux rates, low system productivityand a shorter membrane lifetime.

Thus, there is a strong need to develop new and improved methods thatsolve these issues.

SUMMARY OF THE INVENTION

The present invention in its broadest aspect relates to a method forreducing turbidity of an aqueous phase comprising compounds selectedfrom two or more of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid andphenolic compounds of which at least one compound is selected from PA,PI, LipO and PPO;

-   -   a) providing an aqueous phase comprising compounds selected from        two or more of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid        and phenolic compounds of which at least one compound is        selected from PA, PI, LipO and PPO;    -   b) contacting the aqueous phase with a soluble silicate at a pH        in the range of 3-10 and optionally, a divalent or trivalent        metal ion allowing formation of an insoluble precipitate        comprising said silicate and one or more the compounds selected        from LipO, PPO, pectin, lipid, glycoalkaloid and phenolic        compounds, and optionally, a divalent or trivalent metal ion,        said insoluble precipitate is subsequently removed from the        aqueous phase by physical means;

thereby obtaining an aqueous phase having reduced turbidity compared toan untreated aqueous phase.

The inventors of the present invention have also developed new methodsfor separating and isolating functional plant compounds, methods whichare unexpectedly applicable and useful in industrial scale processing ofplant materials. Accordingly, the present invention provides in a firstaspect a method for isolating a first group of compounds selected fromone or more of patatin protein (PA), protease inhibitor protein (PI),lipoxygenase (LipO) and polyphenol oxidase (PPO) from a second group ofcompounds selected from one or more of PA, PI, LipO, PPO, glycoalkaloidand phenolic compounds said method comprising:

-   -   a) providing an aqueous phase comprising compounds selected from        two or more of PA, PI, PPO, LipO, glycoalkaloid and phenolic        compounds of which at least one compound is selected from PA,        PI, LipO and PPO;    -   b) contacting the aqueous phase with a mobile solubilized ligand        at physico-chemical conditions allowing formation of a complex        between the ligand and the compounds selected from one or more        of PA, PI, LipO and PPO;    -   c) allowing the complex to separate from the aqueous supernatant        phase, optionally by changing said physico-chemical conditions        in the composition to reduce the solubility of the complex; and    -   d) isolating the complex separated from the aqueous phase.

One aspect of the invention relates to a method for isolating a firstgroup of compounds selected from one or more of patatin protein (PA),protease inhibitor protein (PI), lipoxygenase (LipO) and polyphenoloxidase (PPO) from a second group of compounds selected from one or moreof PA, PI, LipO, PPO, pectin, lipid, glycoalkaloid and phenoliccompounds said method comprising;

-   -   a) providing an aqueous phase comprising compounds selected from        two or more of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid        and phenolic compounds of which at least one compound is        selected from PA, PI, LipO and PPO;    -   b) contacting the aqueous phase with a soluble silicate at a pH,        in the range of 3-10 and optionally, a divalent or trivalent        metal ion allowing formation of an insoluble precipitate        comprising said silicate and one or more the compounds selected        from LipO, PPO, pectin, lipid, glycoalkaloid and phenolic        compounds, and optionally, a divalent or trivalent metal ion,        said insoluble precipitate is subsequently removed from the        aqueous phase by physical means;    -   c) contacting the remaining aqueous phase with a mobile        solubilized ligand at physico-chemical conditions allowing        formation of a complex between the ligand and the compounds        selected from one or more of PA, PI, LipO and PPO;    -   d) allowing the complex to separate from the aqueous supernatant        phase, optionally by changing said physico-chemical conditions        in the composition to reduce the solubility of the complex; and    -   e) isolating the complex separated from the aqueous phase.    -   OR    -   f) adjusting pH of the remaining aqueous phase (from step b)) to        allow the formation of a precipitate comprising PA;    -   g) isolating the precipitate from the aqueous phase    -   OR    -   h) subjecting the remaining aqueous phase (from step b)) to a        membrane filtration process separating at least one of PA and PI        in the retentate from at least one of PA, PI, LipO, PPO, pectin,        lipid, glycoalkaloid and phenolic compounds in the permeate.

In a further aspect, the invention provides a composition comprising oneor more of patatin protein (PA), protease inhibitor protein (PI),polyphenol oxidase (PPO) Lipoxygenase (LipO), glycoalkaloid and phenoliccompounds obtainable from the method of the invention.

In further aspects, the invention provides food or beverages, animalfeeds, pet foods, cosmetics, pharmaceuticals, nutraceuticals, dietarysupplements or fermentation broths comprising the composition of theinvention.

In a further aspect, the invention provides use of a composition or aproduct of the invention in a process for providing one or morefunctions selected from foam control, emulsion control, control ofproteolytic activity, nutrition, gelation, solubility, organolepticimprovement, allergenicity reduction and oxidation.

In a further aspect, the invention provides use of a compositioncomprising glycoalkaloid obtained from the method of the invention as amedicament for treating or preventing a disease.

In a further aspect, the invention provides a method for isolating oneor more of glycoalkaloid, LipO and phenolic compounds said methodcomprising:

-   -   a) providing an aqueous phase comprising one or more of        glycoalkaloid, LipO and phenolic compounds and at least one        protein;    -   b) contacting the aqueous phase with a mobile solubilized ligand        at physico-chemical conditions allowing formation of a complex        between the ligand and the protein;    -   c) allowing the complex to separate from the aqueous supernatant        phase, optionally by changing said physico-chemical conditions        in the composition to reduce the solubility of the complex; and    -   d) isolating the one or more of glycoalkaloid, LipO and phenolic        compounds comprised in the aqueous phase from the complex.

In a further aspect, the invention provides a method for isolating oneor more of glycoalkaloid, LipO and phenolic compounds said methodcomprising:

-   -   a) providing an aqueous phase comprising one or more of        glycoalkaloid LipO and phenolic compounds and at least one        protein;    -   b) contacting the aqueous phase with a mobile solubilized ligand        at physico-chemical conditions allowing formation of a complex        between the ligand and the one or more of glycoalkaloid, LipO        and phenolic compounds;    -   c) allowing the complex to separate from the aqueous supernatant        phase, optionally by changing said physico-chemical conditions        in the composition to reduce the solubility of the complex; and    -   d) isolating the one or more of glycoalkaloid, LipO and phenolic        compounds comprised in the complex.

In a further aspect, the invention provides a composition comprising oneor more of glycoalkaloid, LipO and phenolic compounds obtainable fromthe method of the invention.

In a further aspect, the invention provides a method for isolating oneor more proteins comprising contacting an aqueous composition,comprising the one or more proteins with a water soluble siliconcontaining anionic polymer capable of binding to the protein; optionallyadjusting the conditions in the composition to promote binding betweenthe protein(s) and the polymer and causing the bound protein(s) toseparate from the composition, optionally by precipitation, andisolating the separated bound protein(s), optionally comprising one ormore selective elution steps to achieve one or more isolated proteinfractions, optionally separated from the polymer.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1 to 3 :

Illustrates SDS PAGE analysis of test solutions of examples 3 to 5respectively.

FIG. 1

Lane 1: Potato juice (test solution 1)

Lane 2: Supernatant, PA enriched potato juice (test solution 2)

FIG. 2

Lane 1: Potato juice (test solution 1)

Lane 2: Supernatant 5 ml juice per ml adsorbent (test solution 2)

Lane 3: Supernatant 10 ml juice per ml adsorbent (test solution 3)

Lane 4: Supernatant 15 ml juice per ml adsorbent (test solution 4)

FIG. 3

Lane 1: Potato juice (test solution 1)

Lane 2: Supernatant 10 ml juice per ml adsorbent (test solution 2)

Lane 3: Supernatant from sodium alginate precipitation of PA (testsolution 3)

Lane 4: Dissolved precipitate at pH 7.0, highly PA enriched product(test solution 4)

FIG. 4 :

Illustrates SDS PAGE analysis of test solutions of example 22.

FIG. 4

Lane 1: Potato juice (test solution 1)

Lane 2: Supernatant after 10 ml juice per ml adsorbent (test solution 2)

Lane 3: Supernatant after precipitation of PA at pH 3.5 (test solution3)

Lane 4: Dissolved precipitate at pH 7.0 (test solution 4)

FIGS. 5 and 6 :

Illustrates SDS PAGE analysis of test solutions of examples 7.

FIG. 5

Lane 1: Potato juice (test solution 1)

Lane 2: Supernatant (test solution 2)

Lane 3: Wash (test solution 3)

Lane 4: Dissolved precipitate at pH 7.5 (test solution 4)

FIG. 6

Lane 1: Dissolved precipitate pH 7.5 (test solution 4)

Lane 2: Permeate from ultrafiltration (test solution 5)

Lane 3: First diafiltration, permeate (test solution 6)

Lane 4: Second diafiltration, permeate (test solution 7)

Lane 5: Third diafiltration, permeate (test solution 8)

Lane 6: Fourth diafiltration, permeate (test solution 9)

Lane 7: Retentate from ultrafiltration=PA enriched product (testsolution 10)

FIGS. 7 to 22 :

Illustrates SDS PAGE analysis of test solutions of examples 8 to 32respectively.

FIG. 7

Lane 1: Potato juice (test solution 1)

Lane 2: Supernatant A, non-precipitated material (test solution 2)

Lane 3: Wash Elution A 0.2 M NaCl pH 3.5 (test solution 5)

Lane 4: Dissolved precipitate A (test solution 8)

Lane 5: Supernatant B, non-precipitated material (test solution 3)

Lane 6: Wash Elution B with 0.4 M NaCl pH 3.5 (test solution 6)

Lane 7: Dissolved precipitate B at pH 7.5 (test solution 9)

Lane 8: Supernatant C, non precipitated material (test solution 4)

Lane 9: Wash Elution C with 0.6 M NaCl pH 3.5 (test solution 7)

Lane 10: Dissolved precipitate C at pH 7.5 (test solution 10)

FIG. 8

Lane 1: Potato juice (test solution 1)

Lane 2: Supernatant, non-precipitated material (test solution 2)

Lane 3: Wash Elution 0.7 M NaCl pH 3.5 (test solution 3)

Lane 4: Dissolved precipitate (test solution 4)

FIG. 9

Lane 1: Potato juice (test solution 1)

Lane 2: Supernatant pH 4.5 (8 ml juice to 2 ml alginate polymer, testsolution 2)

Lane 3: Supernatant pH 4.0 (8 ml juice to 2 ml alginate polymer, testsolution 3)

Lane 4: Supernatant pH 3.5 (8 ml juice to 2 ml alginate polymer, testsolution 4)

Lane 5: Supernatant pH 4.5 (13 ml juice to 2 ml alginate polymer, testsolution 6)

Lane 6: Supernatant pH 4.0 (13 ml juice to 2 ml alginate polymer, testsolution 7)

Lane 7: Supernatant pH 3.5 (13 ml juice to 2 ml alginate polymer, testsolution 8)

Lane 8: Potato juice (test solution 1)

Lane 9: Supernatant pH 3.0 (8 ml juice to 2 ml alginate polymer, testsolution 5)

Lane 10: Supernatant pH 3.0 (13 ml juice to 2 ml alginate polymer, testsolution 9)

FIG. 10

Lane 1: Potato juice (test solution 1)

Lane 2: First supernatant (test solution 2)

Lane 3: Dissolved precipitate (test solution 3)

Lane 4: Supernatant after second precipitation (test solution 4)

FIG. 11

Lane 1: Potato juice (test solution 1)

Lane 2: Supernatant at pH 4.5 (test solution 2)

Lane 3: Supernatant at pH 4.0 (test solution 3)

Lane 4: Supernatant at pH 3.5 (test solution 4)

FIG. 12

Lane 1: Potato juice (test solution 1)

Lane 2: Supernatant at pH 5.0 (MW 450,000 test solution 2)

Lane 3: Supernatant at pH 4.5 (MW 450,000 test solution 3)

Lane 4: Supernatant at pH 4.0 (MW 450,000 test solution 4)

Lane 5: Supernatant at pH 5.0 (MW 15,000 test solution 5)

Lane 6: Supernatant at pH 4.5 (MW 15,000 test solution 6)

Lane 7: Supernatant at pH 4.0 (MW 15,000 test solution 7)

FIG. 13

Lane 1: Potato juice (test solution 1)

Lane 2: Supernatant pH 4.5 (kappa, test solution 2)

Lane 3: Supernatant pH 4.0 (kappa, test solution 3)

Lane 4: Supernatant pH 3.5 (kappa, test solution 4)

Lane 5: Supernatant pH 4.5 (iota, test solution 5)

Lane 6: Supernatant pH 4.0 (iota, test solution 6)

Lane 7: Supernatant pH 3.5 (iota, test solution 7)

Lane 8: Supernatant pH 4.5 (lambda, test solution 8)

Lane 9: Supernatant pH 4.0 (lambda, test solution 9)

Lane 10: Supernatant pH 3.5 (lambda, test solution 10)

FIG. 14

Lane 1: Potato juice (test solution 1)

Lane 2: Supernatant after pH adjustment to 3.5 (test solution 2)

Lane 3: Wash of precipitate (test solution 3)

Lane 4: Dissolved precipitate (test solution 4)

Lane 5: Supernatant precipitation with lambda carrageenan (test solution5)

Lane 6: Dissolved carrageenan precipitate (test solution 6)

FIG. 15

Lane 1: Potato juice (test solution 1)

Lane 2: Solubilized precipitate without salt wash (test solution 2)

Lane 3: Wash fraction 0.3 M sodium chloride, 5 mM sodium acetate pH 4.5(test solution 3)

Lane 4: Solubilized precipitate after 0.3 M salt wash (test solution 5)

Lane 5: Wash fraction 0.6 M sodium chloride, 5 mM sodium acetate pH 4.5(test solution 4)

Lane 6: Solubilized precipitate after 0.6 M salt wash (test solution 6)

FIG. 16

Lane 1: Potato juice (test solution 1)

Lane 2: Supernatant A, pH 6.1 (test solution 2)

Lane 3: Supernatant B, pH 5.5 (test solution 3)

Lane 4: Supernatant C, pH 4.9 (test solution 4)

Lane 5: Supernatant D, pH 4.5 (test solution 5)

Lane 6: Supernatant E, pH 3.9 (test solution 6)

FIG. 17

Lane 1: Potato juice (test solution 1)

Lane 2: Supernatant pH 6.1 (test solution 2)

FIG. 18

Lane 1: Potato juice (test solution 1)

Lane 2: Supernatant, pH 6.1 (test solution 2)

Lane 3: Supernatant A, pH 2.8 (test solution 3)

Lane 4: Supernatant B, pH 1.9 (test solution 4)

Lane 5: Supernatant C, pH 1.4 (test solution 5)

FIG. 19

Lane 1: Potato juice (test solution 1)

Lane 2: Supernatant A (0.3 ml water glass), pH 6.0 (test solution 2)

Lane 3: Supernatant B (0.6 ml water glass), pH 6.0 (test solution 3)

FIG. 20

Lane 1: Supernatant A (700 mg sodium silicate), pH 6.1 (test solution 2)

Lane 2: Supernatant B (350 mg sodium silicate), pH 6.1 (test solution 3)

Lane 3: Potato juice (test solution 1)

Lane 4: Supernatant C (calcium silicate), pH 6.0 (test solution 4)

FIG. 21

Lane 1: Potato juice (test solution 1) pre-treated with CaCl2) and waterglass

Lane 2: Supernatant from alginate precipitation pH 3.5 (test solution 2)

Lane 3: Retentate from ultrafiltration (test solution 6, product 2)

Lane 4: Dissolved alginate precipitate, pH 10 (test solution 3, product1)

Lane 5: Permeate from ultrafiltration (test solution 4)

Lane 6: Pool of diafiltration fractions (test solution 5)

FIG. 22

Lane 1: Potato juice (test solution 1)

Lane 2: Potato juice pre-treated with water glass (test solution 2)

Lane 3: Supernatant from pH adjustment to 3.0 (test solution 3)

Lane 4: Dissolved alginate precipitate, pH 9 (test solution 4)

The present invention will now be described in more detail in thefollowing.

DETAILED DESCRIPTION OF THE INVENTION Definitions

The term “patatin”, also denoted herein as “PA”, means storageglycoproteins found in potatoes (Solanum tuberosum). Patatin representsa group of immunologically identical glycoprotein isoforms withmolecular mass in the range of 40-43 kDa. Patatin also have phospolipaseactivity capable of cleaving fatty acids from membrane lipids. Forpurposes of the invention PA may be determined by different knownassays, including SDS-PAGE combined with scanning densitometry asdescribed herein (e.g. using a GS-900™ Calibrated Densitometer fromBIO-RAD Laboratories, USA) including all protein bands in the molecularweight region between 35 kD and 60 kD the PA category, ELISA testingusing patatin specific antibodies, as well as enzymatic assays specificfor the phospholipase activity (see e.g. Lipids, 2003, 38(6):677-82.“Determination of the phospholipase activity of patatin by a continuousspectrophotometric assay.” Jiménez-Atiénzar M et al.

The term “protease inhibitor”, also denoted herein as “PI”, meansproteins, which possess molecular weights ranging from about 3 kD toabout 35 kD, e.g. found in potatoes (Solanum tuberosum) and other plantssuch as soy and lupin, animals and microorganisms capable of inhibitingthe activity of e.g. serine proteases, cysteine proteases, aspartateproteases, and metalloproteases. For purposes of the invention PI, ine.g. potato derived samples, may be determined by different knownassays, including SDS-PAGE combined with scanning densitometry asdescribed herein (e.g. using a GS-900™ Calibrated Densitometer fromBIO-RAD Laboratories, USA) including all protein bands in the molecularweight region between 3 kD and 35 kD in the PI category, and morebroadly by enzyme inhibition assays as generally described in the art(see e.g. The Open Food Science Journal, 2011, 5:42-46. “QuantitativeDetermination of Trypsin Inhibitory Activity in Complex Matrices”. RobinE. J. Spelbrink et al.).

The term “polyphenol oxidase”, also denoted herein as “PPO”, meansproteins found in nearly all plant tissues including potatoes (Solanumtuberosum), and can also be found in bacteria, animals, and fungi.Polyphenol oxidase (tyrosinase) (TY) is a bifunctional,copper-containing oxidase having both catecholase and cresolaseactivity. PPO causes the rapid polymerization of o-quinones to produceblack, brown or red pigments (polyphenols) which cause fruit browning.The amino acid tyrosine contains a single phenolic ring that may beoxidised by the action of PPOs to form o-quinone. Hence, PPOs may alsobe referred to as tyrosinases. The catalytic action of PPO has anegative impact on the quality of several fruit and vegetable crops andresults in alteration of color, flavor, texture, and nutritional value.It is a limiting factor in the handling and technological processing ofcrops as peeled, sliced, bruised or diseased tissues rapidly undergobrowning. For purposes of the invention PPO may be determined bydifferent known assays as reviewed in: Journal of Food Biochemistry2003, 27(5):361-422. “Physicochemical properties and function of plantpolyphenol oxidase: A review”. Ruhiye Yoruk et al.

The term “lipoxygenase”, also denoted herein as “LipO”, means proteinsfound in found in plants, animals and fungi capable of catalyzing thedioxygenation of polyunsaturated fatty acids. Lipoxygenases havefood-related applications in bread making and aroma production but theyalso have negative implications for the color, off-flavour andantioxidant status of plant-based foods. In potatoes (Solanum tuberosum)lipoxygenase has a molecular weight of approx. 97 kD and can be detectedby SDS-PAGE (see e.g. FEBS Journal, 2006, 273, 3569-3584 “Patatins,Kunitz protease inhibitors and other major proteins in tuber of potatocv. Kuras” Guy Bauw et al.). For purposes of the invention LipO may bedetermined by different known assays, including SDS-PAGE combined withscanning densitometry as described herein (e.g. using a GS-900™Calibrated Densitometer from BIO-RAD Laboratories, USA) as wells asenzyme activity assays as described in e.g. J. Agric. Food Chem., 2001,49, 32-37. “Colorimetric Method for the Determination of LipoxygenaseActivity”. Gordon E. Anthon et al.

The term “glycoalkaloid” or “alkaloid glucoside” means a family ofchemical compounds derived from alkaloids in which sugar groups areappended. There are several that are potentially toxic, most notablythose which are the poisons commonly found in the plant species Solanumdulcamara (nightshade). A prototypical glycoalkaloid is solanine(composed of the sugar solanose and the alkaloid solanidine), which isfound in potatoes (Solanum tuberosum). For purposes of the inventionglycoalkaloid may be determined by different known assays, including astandard HPLC assay as described Eng. Life Sci., 2005, 5, 562-567.“Optimization of glycoalkaloid analysis for us in industrial potatofruit juice downstreaming”. Alt, V., Steinhof et al.

The term “ligand” means a molecule comprising a functional group ormoiety capable binding to another molecule by non-covalent bonds, suchas of hydrogen bonds, hydrophobic bonds, π-π (pi-pi) bonds and ionicbonds.

The term “complex” means a molecule bound to a ligand by non-covalentbonds, such as of hydrogen bonds, hydrophobic bonds, π-π (pi-pi) bondsand ionic bonds.

The term “protein:ligand dry weight ratio” means the dry weight ratio ina complex between a protein and the molecule comprising the ligand. Iffor example the ligand is a polymer comprising a multitude of functionalgroups bound to a protein, then the protein:ligand dry weight ratio isthe ratio between the dry weight of protein in the complex and the dryweight of polymer in the complex.

The term “dry weight” means the weight or mass of a substance remainingafter removal of water by heating to constant weight at 110 degreesCelcius. The dry weight per ml sample is thus the weight or mass of asubstance remaining after removal of water by heating to constant weightat 110 degrees Celcius per ml sample applied to drying.

The term “isolating” or “separating” means any human intervention whichchange the relative amount of the compound compared to another selectedconstituent in a given matrix to a higher relative amount of thecompound relative to the other constituent. In an embodiment, thecompound may be isolated into a pure or substantially pure form. In thiscontext, a substantially pure compound means that the compoundpreparation contains less than 10%, such as less than 8%, such as lessthan 6%, such as less than 5%, such as less than 4%, such as less than3%, such as less than 2%, such as less than 1%, such as less than 0.5%by weight of other selected constituents. In an embodiment, an isolatedcompound is at least 50% pure, such as at least 60% pure, such as atleast 80% pure, such as at least 90% pure, such as at least 91% pure,such as at least 92% pure, such as at least 93% pure, such as at least94% pure, such as at least 95% pure, such as at least 96% pure, such asat least 97% pure, such as at least 98% pure, such as at least 99% pure,such as at least 99.5% pure, such as 100% pure by dry weight.

The term “synthetic” or “non-naturally occurring” means that A compoundis not normally found in nature or natural biological systems. In thiscontext, the term “found in nature or in natural biological systems”does not include the finding of a compound in nature resulting fromreleasing the compound to nature by deliberate or accidental humanintervention. Synthetic compounds may include compounds completely orpartially synthetized by human intervention and/or compounds prepared byhuman modification of a natural compound.

The term “membrane separation process” refers to a process using asemi-permeable membrane, allowing only compounds having a size lowerthat a certain value to pass, to separate molecules of a higher size ina liquid or gas continuous phase composition from molecules of a lowersize. In this context, liquid or gas continuous phase compositions areto be understood in the broadest sense, including both single phasecompositions such as solutions or gases, and dual phase compositionssuch as slurries, suspensions or dispersions wherein a solid isdistributed in a liquid or gas phase.

The term “retentate” means compounds which are not allowed to pass aselected membrane in a which have a membrane separation process.

The term “permeate” or “filtrate” means compounds which canhas passed aselected membrane in a which have a membrane separation process.

The term “precipitation” refers to the phenomenon that a dissolvedcompound exceeding its solubility in the solvent undergoes a phasetransition from a dissolved liquid state to a solid state. Precipitationis often caused by a chemical reaction and/or a change in the solutionconditions. The solidified compound is referred to as the “precipitate”.

The term “diafiltration” means a technique that uses ultrafiltrationmembranes to completely remove, replace, or lower the concentration ofsalts or solvents from solutions containing proteins, peptides, nucleicacids, and other biomolecules. The process selectively utilizespermeable (porous) membrane filters to separate the components ofsolutions and suspensions based on their molecular size. Anultrafiltration membrane retains molecules that are larger than thepores of the membrane while smaller molecules such as salts, solventsand water, which are 100% permeable, freely pass through the membrane.In a diafiltration process the retentate is added water or a buffercomposition while the membrane filtration process continuously removeswater, salts and low molecular weight compounds to the permeate side ofthe membrane.

The term “adsorption” means a process in which molecules from a gas,liquid or dissolved solid adhere to a surface of a solid phaseadsorbent. Likewise, and adsorbent (also named a solid phase adsorbent)is an insoluble material on which adsorption can occur.

The term “mobile solubilized”, as used herein about a ligand, means thatthe ligand which is at least partially dissolved in a solvent and issufficiently mobile allowing the ligand to form complexes with acompound dissolved in the solvent. Thus, mobile solubilized ligands are,in contrast to solid phase adsorbents, at least partially dissolved in asolvent. Fully dissolved “mobile solubilized” ligands form homogeneoussolutions in a solvent while partly dissolved “mobile solubilized”ligands form colloidal dispersions or solutions.

The term “immobilized solid carrier” means a solid phase adsorbent whichmay be in the form of insoluble, permeable or impermeable, materialssuch as spherical or amorphous beads or fibers, or membranes.

The term “water activity” in a solution is defined as:aw=p/p0

where p is the vapor pressure of water over the solution, and p□ is thevapor pressure of pure water at the same temperature.

The term “pectin” means pectic polysaccharides, which are rich ingalacturonic acid. The amount, structure and chemical composition ofpectin differs among plants, within a plant over time, and in variousparts of a plant. In natural pectins around 80 percent of carboxylgroups of galacturonic acid are esterified with methanol or areacetylated.

The term “phenolic compounds” means aromatic or heteroaromatic compoundscomprising one or more ring systems and one or more phenolic hydroxylgroups.

The term “potato” means the tubers of plant genus Solanum, particularlythe species S. tuberosum.

The term “protein concentration” means the amount of protein per literof a sample calculated as the total weight or mass of amino acids perliter as determined according to EUROPEAN PHARMACOPOEIA 5.0 section2.2.56. AMINO ACID ANALYSIS or by determination of total nitrogen in asample by the method of Kjeldahl using the conversion factor N×6.25. Allsamples are dialyzed against demineralized water in dialysis tubingcellulose membrane (Sigma-Aldrich, USA, cat. No.: D9652) to remove anyfree amino acids and low molecular weight peptides prior to the aminoacid determination.

The term “silicon containing anionic polymer” means a polysilicate orpolysiloxane (silicone) or mixtures of these. Silicates are compoundsformed by the reaction of the acidic oxide silica (SiO₂) with variousbasic metal oxides. Silicates contain silicon oxo anions which possesscovalent Si—O bonds. These compounds have 2-coordinate oxygen atoms thatlink silicon atoms together into oligomeric or one-, two-, orthree-dimensional polymers. Polysiloxane (or silicone) are polymerizedsiloxanes, silicones consist of an inorganic silicon-oxygen backbonechain (⋅⋅⋅—Si—O—Si—O—Si—O—⋅⋅⋅) with organic side groups attached to thesilicon atoms. These silicon atoms are tetravalent. So, silicones arepolymers constructed from inorganic-organic monomers. Silicones have ingeneral the chemical formula [R₂SiO]n, where R is an organic group. Inthe context of the invention silicates and silanes are defined as beingpolymers.

The term “soluble” means solubility in water at a concentration of atleast 1 g/L at 25 degrees Celsius.

The term “solubilized silicon containing anionic polymer” means asolution of the polymer (as opposed to the solid polymer without addedsolvent). The solution may be saturated and non-dissolved polymer may bepresent in the solution.

The term “anionic polymer” means a polymer carrying one or more negativecharges in solution.

The term “comprise” and “include” as used throughout the specificationand the accompanying items/claims as well as variations such as“comprises”, “comprising”, “includes” and “including” are to beinterpreted inclusively. These words are intended to convey the possibleinclusion of other elements or integers not specifically recited, wherethe context allows.

The articles “a” and “an” are used herein to refer to one or to morethan one (i.e. to one or at least one) of the grammatical object of thearticle. By way of example, “an element” may mean one element or morethan one element.

The Method for Isolating Protein Compounds from Plant Material

The present inventors have surprisingly found that certain combinationsof processing steps, each providing specific improvements to the purityof the proteins, can provide both the protein quality and the industrialapplicability, robustness and profitability which enables a long-neededsolution to the valorization of the very large volume of liquidside-streams resulting from the starch manufacturing industry.

Such solution will not only bring value to the starch and potatoindustry but also mean an increased production of plant derived foodgrade proteins that can supplement and substitute the animal derivedproteins which—due to the intensive animal farming associated with it—isan increasing burden to the environment and is predicted soon to becomea scarce resource.

With one objective being to prepare industrial scale isolates of usefulcompounds present in plant materials, in particular in tubers of plantsof the genus Solanum, such as S. tuberosum the inventors of thisinvention have developed and provided a method for isolating a firstgroup of compounds selected from one or more of patatin protein (PA),protease inhibitor protein (PI), lipoxygenase (LipO) and polyphenoloxidase (PPO) from a second group of compounds selected from one or moreof PA, PI, LipO, PPO, glycoalkaloid and phenolic compounds said methodcomprising:

a) providing an aqueous phase comprising compounds selected from two ormore of PA, PI, PPO, LipO, glycoalkaloid and phenolic compounds of whichat least one compound is selected from PA, PI, LipO and PPO;

b) contacting the aqueous phase with a mobile solubilized ligand atphysico-chemical conditions allowing formation of a complex between theligand and the compounds selected from one or more of PA, PI, LipO andPPO;

c) allowing the complex to separate from the aqueous supernatant phase,optionally by changing said physico-chemical conditions in thecomposition to reduce the solubility of the complex; and

d) isolating the complex separated from the aqueous phase.

It is to be understood that in one embodiment a compound selected in thefirst group is deselected in the second group. It is also to beunderstood that in another embodiment the aqueous phase of step a)comprises a compound selected from one or more of PA, PI, PPO and acompound selected from one or more of glycoalkaloid, LipO and phenoliccompounds.

This method has demonstrated unexpectedly useful for industrial scaleseparation of useful compounds from undesirable compounds, because plantmaterials applied in industry often are unprocessed and raw both topreserve nutritional value and to save costs. For example, whenprocessing potatoes into e.g. potato starch usually unpeeled potatoesare used and since many unwanted compounds are present in the peel, itmay be important to be able to remove such unwanted compounds from thewanted ones.

In an embodiment of the invention the separated complex comprises acombination of PA and PI and PPO and wherein the complex is separatedfrom the aqueous supernatant phase by precipitation.

In an embodiment the precipitate is enriched in PA compared to othercompounds so that the dry weight ratio PA:PI in the precipitate ispreferably higher than the dry weight PA:PI ratio for PA and PIremaining dissolved in the aqueous supernatant phase. In this embodimentthe enriched precipitate may be further processed by re-dissolving theprecipitated complex in an aqueous solvent and further isolating PA fromthe PI and PPO by a mechanical separation process concentrating the PAin the retentate. As an alternative in this embodiment the PA-enrichedprecipitated complex may also be isolated without re-dissolution, by amechanical separation process concentrating one or more of PA, PI andPPO in the retentate. In this embodiment, further the aqueoussupernatant phase remaining from the PA enriched precipitate may be

a) contacted with a further mobile solubilized ligand atphysico-chemical conditions in the aqueous supernatant phase allowingformation of a complex between the ligand and compounds selected fromone or more of PI, and PPO remaining in the aqueous supernatant phase;

b) allowing the complex to separate from the aqueous supernatant phase,optionally by changing said physico-chemical conditions in thecomposition to reduce the solubility of the complex so that the complexseparates from the aqueous supernatant phase; and

c) isolating the complex.

In another embodiment, the precipitate comprises the majority of PA andPI, so that the sum of PA and PI remaining dissolved in the aqueoussupernatant phase is less than 20 wt %, optionally less than 10 wt. %,optionally less than 5 wt %, optionally less that 1 wt % of the total PAand PI (depletion of PA and PI in the aqueous phase). In thisembodiment, the precipitate may be further processed by dissolving theprecipitated complex in an aqueous solvent and isolating PA from one ormore compounds selected from PI, and PPO by a mechanical separationprocess concentrating the PA in the retentate. As an alternative in thisembodiment the precipitated complex may also be isolated withoutre-dissolution, by a mechanical separation process concentrating one ormore of PA, PI and PPO in the retentate. As a further alternative inthis embodiment, the precipitate may be further processed by dissolvingthe precipitated complex in an aqueous solvent and isolating PA from oneor more compounds selected from PI and PPO by selectively adsorbing theone or more compounds selected from PI and PPO on an immobilized solidcarrier at conditions where the carrier will bind the one or morecompounds selected from PI and PPO.

In another embodiment of the invention the dry weight ratios PI:PA orPPO:PA in the precipitate is higher than the dry weight ratios PI:PA orPPO:PA for PA, PI and PPO remaining dissolved in the aqueous supernatantphase. In this embodiment, the method may further comprise concentratingPA in the aqueous supernatant phase by a mechanical separation processconcentrating PA in the retentate, optionally combined withdiafiltation. As an alternative in this embodiment, the method mayfurther comprise:

a) contacting the aqueous supernatant phase with a further mobilesolubilized ligand at physico-chemical conditions in aqueous supernatantphase allowing formation of a complex between the ligand and PA;

b) allowing the complex to separate from the aqueous supernatant phase,optionally by changing said physico-chemical conditions in thecomposition to reduce the solubility of the complex so that the complexseparates from the aqueous supernatant phase; and

c) isolating the complex.

In a further embodiment, the method of the invention further comprisesadsorbing dissolved PA in the aqueous supernatant phase on animmobilized solid carrier at conditions where the carrier will bind PA.

In a further embodiment the method of the invention further comprisespre-treating the aqueous phase by adsorbing one or more of PI, LipO andPPO on an immobilized solid carrier at conditions where the carrier willbind the one or more of PI, LipO or PPO.

An aspect of the present invention relates to a method for reducingturbidity of an aqueous phase comprising compounds selected from two ormore of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid and phenoliccompounds of which at least one compound is selected from PA, PI, LipOand PPO;

-   -   a) providing an aqueous phase comprising compounds selected from        two or more of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid        and phenolic compounds of which at least one compound is        selected from PA, PI, LipO and PPO;    -   b) contacting the aqueous phase with a soluble silicate at a pH        in the range of 3-10, allowing formation of an insoluble        precipitate comprising said silicate and one or more the        compounds selected from LipO, PPO, pectin, lipid, glycoalkaloid        and phenolic compounds, said insoluble precipitate is        subsequently removed from the aqueous phase by physical means;

thereby obtaining an aqueous phase having reduced turbidity compared toan untreated aqueous phase.

In another aspect, the invention provides a method for isolating a firstgroup of compounds selected from one or more of patatin protein (PA),protease inhibitor protein (PI), lipoxygenase (LipO) and polyphenoloxidase (PPO) from a second group of compounds selected from one or moreof PA, PI, LipO, PPO, pectin, lipid, glycoalkaloid and phenoliccompounds said method comprising

a) providing an aqueous phase comprising compounds selected from two ormore of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid and phenoliccompounds of which at least one compound is selected from PA, PI, LipOand PPO;

b) performing one or more steps to reduce the concentration of solaninein the dry matter of the aqueous phase with at least 5 percent, and toachieve an optical density at 620 nm of the remaining aqueous phase ofless than 0.7;

thereby obtaining an aqueous phase having reduced turbidity compared toan untreated aqueous phase.

In one embodiment of the invention the precipitate in step b) of themethods of the present invention comprise at least 10% of the PAinitially present in the aqueous phase, such as at least 20%, such as atleast 30%, such as at least 50%, such as at least 70%, such as at least85%, such as at least 90% of the PA initially present in the aqueousphase.

The present invention may in one embodiment be described as a method forisolating a first group of compounds selected from one or more ofpatatin protein (PA), protease inhibitor protein (PI), lipoxygenase(LipO) and polyphenol oxidase (PPO) from a second group of compoundsselected from one or more of PA, PI, LipO, PPO, pectin, lipid,glycoalkaloid and phenolic compounds said method comprising

a) providing an aqueous phase comprising compounds selected from two ormore of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid and phenoliccompounds of which at least one compound is selected from PA, PI, LipOand PPO;

b) contacting the aqueous phase with a soluble silicate at a pH, in therange of 3-10 and optionally, a divalent or trivalent metal ion allowingformation of an insoluble precipitate comprising said silicate and oneor more the compounds selected from LipO, PPO, pectin, lipid,glycoalkaloid and phenolic compounds, and optionally, a divalent ortrivalent metal ion, said insoluble precipitate is subsequently removedfrom the aqueous phase by physical means;

c) contacting the remaining aqueous phase with a mobile solubilizedligand at physico-chemical conditions allowing formation of a complexbetween the ligand and the compounds selected from one or more of PA,PI, LipO and PPO;

d) allowing the complex to separate from the aqueous supernatant phase,optionally by changing said physico-chemical conditions in thecomposition to reduce the solubility of the complex; and

e) isolating the complex separated from the aqueous phase.

OR

f) adjusting pH of the remaining aqueous phase (from step b of themethods of the present invention)) to allow the formation of aprecipitate comprising PA;

g) isolating the precipitate from the aqueous phase

OR

h) subjecting the remaining aqueous phase (from step b of the methods ofthe present invention)) to a membrane filtration process separating atleast one of PA and PI in the retentate from at least one of PA, PI,LipO, PPO, pectin, lipid, glycoalkaloid and phenolic compounds in thepermeate

Siicates and Polymers Such as Silicate

The polymer of the invention may be an inorganic polymer, optionallycomprising one or more organic groups. Such an inorganic polymer maycomprise silicon, optionally in the form of silicate or silicone, suchas polymeric sodium silicate or polymeric silicone or a combinationthereof. In a preferred embodiment the polymer is a solubilized siliconcontaining anionic polymer.

Sodium silicate is the common name for compounds with the formulaNa₂(SiO₂)nO. A well-known member of this series is sodium metasilicate,Na₂SiO₃. Also, known as water glass or liquid glass, these materials areavailable in aqueous solution and in solid form.

For silicate and silicone based polymers, it has unexpectedly been foundthat in order to form the right conformation for binding the compoundsof the invention, the complexing reaction should be done by firstsolubilizing the polymer such that it is in aqueous solution prior tocontacting the compound of the invention with the polymer carrying theligand. Thus, it has surprisingly been found that in some embodimentsthe efficiency of the complex formation and separation is significantlylower if the solid (non-solubilized) polymer is added directly to thecomposition.

In one embodiment, the silicate is sodium silicate, or a siliconcontaining anionic polymer as describe above. In another embodiment, thesilicate is sodium alginate.

The silicate concentration is in the range of 0.2-5 g/L in the presentcontext may preferably in the range of 0.5-3 g/L, 0.5-4 g/L, 0.5-5 g/L,1-3 g/L, 1-4 g/L, 1-5 g/L, 1.5-3 g/L, 1.5-4 g/L, 1.5-5 g/L, 2-3 g/L, 2-4g/L, 2-5 g/L, 2.5-3 g/L, 2.5-4 g/L, or 2.5-5 g/L. The silicateconcentration may be in the range of 0.2-5 g/L, preferably in the rangeof 0.5-3 g/L.

In one embodiment, the invention relates to a method as described above,wherein the silicate concentration is in the range of 0.2-5 g/L.

Metal Ions

In one embodiment, the invention relates to a method, wherein theconcentration of the divalent or trivalent metal ion in the aqueousphase is between 2-100 mM, such as but not limited to the range of 2-50mM, 3-40 mM, 4-40 mM or 5-25 mM.

In one embodiment, the invention relates to a method, wherein thedivalent or trivalent metal ion is a calcium, magnesium or aluminum ion.

Thus, one embodiment of the present invention relates to a method of thepresent invention, wherein step b) further comprises addition of adivalent or trivalent metal ion at a concentration in the aqueous phaseof between 2-100 mM.

The divalent or trivalent metal ion may be a calcium, magnesium oraluminum ion.

Physical Means for Removal of Supernatant

In one embodiment, the invention relates to a method, wherein thephysical means in step b) of the methods of the present invention iscentrifugation and the supernatant is subsequently removed.

In one embodiment, the invention relates to a method, wherein theprecipitate is washed by resuspension in water and pH adjusted to 3.0with hydrochloric acid and centrifuged and the supernatant removed.Other pH levels may be applicable depending on the intended use, andsuch levels is contemplated by the disclosure herein such as but notlimited to pH between 2-5.

In one embodiment, the invention relates to a method, wherein the washedprecipitate is suspended in water and pH is slowly adjusted to pH 7-10with e.g. 1 M NaOH.

In one embodiment, the invention relates to a method, wherein thephysical means in step b) of the methods of the present invention iscentrifugation and the supernatant is subsequently removed.

In one embodiment of the invention the isolation of the precipitate fromthe aqueous phase in step c of the methods of the present invention isperformed using a decanter centrifuge.

In one embodiment of the invention the isolated precipitate in step c)of the methods of the present invention is further treated to produce aprotein powder as an animal feed product. In one embodiment, theprecipitate is washed with an aqueous solution of an acid and dried.

Reduction of Optical Density

In one embodiment of the present invention is the optical density at 620nm of the remaining aqueous phase less than 0.8. The optical density maybe less than 0.7. The optical density may be less than 0.6. The opticaldensity may be less than 0.5. The optical density may be less than 0.2.The optical density may be less than 0.1.

The reduction of the concentration of solanine in step b) of the methodsof the present invention can be done by changing the physico-chemicalconditions by any of the methods mentioned herein, including contactingthe aqueous phase with soluble silicate (see below).

In one embodiment of the present invention is the reduction of theconcentration of solanine (step b above) of the methods of the presentinvention and achieving an optical density at 620 nm of the remainingphase the result of two or more independent steps.

In another embodiment of the present invention is the reduction of theconcentration of solanine (step b above) of the methods of the presentinvention and achieving an optical density at 620 nm of the remainingphase the result of a single step.

Example 24 shows an experimental basis for a single step. Here is asingle step with treatment using silicate and calcium used to achieve areduction in turbidity and solanine.

Thus, the one or more steps needed to achieve the reduction of theconcentration of solanine (step b of the methods of the presentinvention) and achieving an optical density at 620 nm of the remainingphase can comprise any of the procedures for reducing turbiditymentioned herein. For example a combined step with treatment usingsilicate and calcium.

However, in a certain aspect of the invention the one or more stepsneeded to achieve the reduction of the concentration of solanine (step bof the methods of the present invention) and achieving an opticaldensity of the remaining aqueous phase of less than 0.7 may surprisinglycomprise a complete or partial precipitation of PA and other impuritiesessentially without the co-precipitation of PI, which may then beisolated and concentrated with a high yield, high purity and exceptionalhigh clarity. This is exemplified in the experimental section of thepresent disclosure, including example 33.

Thus, a further aspect of the present invention relates to a method forisolating a first group of compounds selected from one or more ofpatatin protein (PA), protease inhibitor protein (PI), lipoxygenase(LipO) and polyphenol oxidase (PPO) from a second group of compoundsselected from one or more of PA, PI, LipO, PPO, pectin, lipid,glycoalkaloid and phenolic compounds said method comprising

a) providing an aqueous phase comprising compounds selected from two ormore of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid and phenoliccompounds of which at least one compound is selected from PA, PI, LipOand PPO;

b) adjusting pH of the aqueous phase to allow the formation of aprecipitate comprising at least 10% of the PA initially present in theaqueous phase and to achieve an optical density at 620 nm of theremaining aqueous phase of less than 0.7;

c) isolating the precipitate from the aqueous phase

d) isolating PI from the remaining aqueous phase (from step c)).

In one embodiment of the invention the optical density at 620 nm of theremaining aqueous phase in step b) of the methods of the presentinvention is less than 0.5;

such as less than 0.3; such as less than 0.2; such as less than 0.1;such as less than 0.07

In another embodiment of the present invention is the concentration ofsolanine in the dry matter of the remaining aqueous phase in step b) ofthe methods of the present invention reduced with at least 5 percent.

In one embodiment, the invention relates to a method, wherein step b) ofthe methods of the present invention comprises performing one or moresteps to reduce the concentration of solanine in the dry matter of theaqueous phase with at least 5 percent.

In one embodiment, the invention relates to a method, wherein step b) ofthe methods of the present invention comprises performing one or moresteps to reduce the concentration of solanine in the dry matter of theaqueous phase with at least 25 percent.

In one embodiment, the invention relates to a method, wherein step b) ofthe methods of the present invention comprises performing one or moresteps to reduce the concentration of solanine in the dry matter of theaqueous phase with at least 15 percent, and to achieve an opticaldensity at 620 nm of the remaining aqueous phase of less than 0.7.

Time and Temperature

In one embodiment, the invention relates to a method, wherein theformation of an insoluble precipitate in step b) of the methods of thepresent invention is made by incubating the aqueous phase for less than120 min, preferably less than 60 min, preferably less than 30 min,preferably less than 15 min.

In one embodiment, the invention relates to a method, wherein theformation of an insoluble precipitate in step b) of the methods of thepresent invention is made by incubating the aqueous phase at 15-50° C.,preferably at 20-45° C., preferably at 22-40° C., preferably at 25-35°C. As shown in Example 30 elevation of the temperature makes the processfaster, which may be desirable in commercial settings.

In one embodiment of the invention the aqueous phase in step b) of themethods of the present invention has a temperature in the range of 20-62degrees Celsius, such as in the range of 24-48 degrees Celsius, such asin the range of 30-45 degrees Celsius, such as in the range of 35-45degrees Celsius, such as in the range of 41-60 degrees Celcius, such asin the range of 45-58 degrees Celcius, such as in the range of 48-58degrees Celcius.

In one embodiment of the invention pH adjustment in step b) of themethods of the present invention is performed less than 200 minutesafter the fruit juice has been released from the potatoes, such as lessthan 150 minutes, such as less than 100 minutes, such as less than 60minutes, such as less than 30 minutes, such as less than 20 minutes,such as less than 10 minutes, such as less than 5 minutes after thefruit juice has been released from the potatoes.

In one embodiment of the invention the formation of an insolubleprecipitate in step b) of the methods of the present invention is madeby incubating the aqueous phase for less than 120 min.

In one embodiment of the invention the formation of an insolubleprecipitate in step b) of the methods of the present invention is madeby incubating the aqueous phase at 15-50° C.

No Use of Synthetic Polymers

Common water-soluble silicates like sodium silicate and sodiummeta-silicate, also known in the form of highly concentrated solutionsas “water glass”, are naturally occurring inorganic compounds that arepresent in small concentrations in most living organisms and findwidespread use both as food processing aids, for pharmaceutical productsand for many technical applications.

Addition of synthetic polymers into food materials or contacting of foodraw materials with synthetic polymers, such as e.g. polyacrylamidederivatives and anionic polyacrylamides, is generally unwanted due tothe risk of unknown toxicological effects arising in the food matrix.For certain applications, such synthetic polymers may be used asnon-ingredient process aids but must in any case be scrutinized andapproved for the purpose by proper regulatory affairs which is a costlyand lengthy process. Common to all of these it must further be assuredthat the synthetic polymer does not migrate into the final food productposing a risk to the consumers.

In the present context, the formation of an insoluble precipitate in themethods of the present invention does not comprise contacting theaqueous phase with a synthetic anionic acrylamide.

In one embodiment of the invention step b) of the methods of the presentinvention does not comprise the addition of a synthetic polymer.

In one embodiment of the invention step b) of the methods of the presentinvention does not comprise the addition of an acrylic polymer.

Mobile Solubilized Ligand

The mobile solubilized ligand of the invention is in principle anyligand which is soluble in aqueous solution and capable of binding to acompound of the invention and separate from the aqueous phase, bychanging its conditions. However in particular, the ligand of theinvention is a functional group of a polymer, said functional group inan embodiment being selected from one or more of a hydrophobic group, anamphiphilic group and a hydrophilic group, optionally an organic group.In particular, the ligand may be selected from one or more of anionicgroups, cationic groups, aryl groups, aromatic groups, heteroaromaticgroups and alkyl groups. More particularly, the functional group may beselected from one or more of carboxyl, sulphate, sulphonate, phosphate,phosphonate, silicate and silicone groups, such as groups selected fromone or more of aromatic sulfonic acids including polystyrene sulfonicacid (PSS), aromatic carboxylic acids, aromatic phosphonic acids.

The ligand of the invention is capable of binding to PA, PI, LipO or PPOby bonds selected from one or more of hydrogen bonds, hydrophobic bonds,π-π (pi-pi) bonds and ionic bonds.

In an embodiment of the invention the polymer of the invention has anaverage molecular size of at least 500 KDa, optionally at least 1500,optionally at least 5.000 kDa, optionally between 5.000 to 10.000.000KDa, optionally between 10.000 to 1.000.000 KDa, optionally between10.000 to 500.000 KDa, optionally between 10.000 to 200.000 KDa,optionally between 12.000 to 190.000 KDa. optionally between 200.000 to400.000 KDa,

The polymer of the invention carrying the ligand may be linear orbranched and may in aqueous solution at pH 7 and 20° C. have asolubility of at least 50 g/L, optionally at least 100 g/L. The polymerof the invention may further be an aqueous solution at a concentrationof 50 g/L, at pH 7 and at 20° C. have a shear viscosity of less than100000 cP, optionally less than 50000, optionally less than 25000 cP.

In a further embodiment, the polymer of the invention carrying theligand provides in aqueous solution a shear thinning liquid, a Newtonianliquid or a thixotropic liquid.

The polymer of the invention carrying the ligand has in an embodiment anisoelectric point of less than pH 4, while it in another embodiment inaqueous solution has a net negative charge at pH less than 7, optionallyless than pH 6, optionally less than pH 5, optionally less than pH 4.5,optionally less than pH 4.0.

In a further embodiment, the polymer of the invention comprises inaqueous solution at pH 7 at least 0.5 millimoles anionic groups per grampolymer, such as at least 2 millimoles anionic groups per gram polymer,such as at least 4 millimoles anionic groups per gram polymer, such asbetween 0.5 to 8 millimoles anionic groups per gram polymer, such as 1to 7 millimoles anionic groups per gram polymer, such between 2 to 6millimoles anionic groups per gram.

Accordingly, in an embodiment the silicon containing polymer issolubilized prior to contacting with the compounds selected from two ormore of PA, PI, PPO, LipO, glycoalkaloid and phenolic compounds and in afurther embodiment the silicon containing polymer is dissolved in theaqueous composition under conditions which do not lead to formation ofsubstantial amounts of separated proteins until the conditions have beenadjusted to effect separation. Further, the silicon containing polymermay advantageously be dissolved in the aqueous composition at pH 7 orhigher, optionally at pH 8 or higher, optionally at pH 9 or higher,optionally at pH 10 or higher. In addition, precipitation of proteinbound to the silicon containing polymer is caused by adjusting pH tobelow pH 8, optionally to below 7, optionally to below pH 6.5,optionally to a pH between 1 to 9, optionally to a pH between 2 to 8,optionally to a pH between 3 to 7, optionally to a pH between 3.5 to6.5, optionally to a pH between 4.5 to 6.5, optionally to a pH between5.5 to 6.5. The silicon containing polymer is preferably a metalsilicate such as selected from one or more of sodium silicate, potassiumsilicate, ammonium silicates, quaternary ammonium silicates. Onepreferred mertal silicate is water glass (sodium metasilicate). Thesilicon containing polymer may also comprise silicone moieties,optionally in a mixture with silicates. The silicone moieties maycomprise an organic functional group capable of binding to proteins andthe organic functional group may comprise a hydrophobic group such as aC2-C12 branched or un-branched alkyl group, an aromatic orheteroaromatic ring system or combinations of these. The organicfunctional group may also comprise one or more anionic groups, one ormore cationic groups or combinations of these. In an embodiment. Thesilicone moieties may be derived from the a reactive silane, optionallyglycidoxypropyl or allyl silane, optionally3-Glycidoxypropyldimethoxymethylsilane,3-Glycidoxypropyldimethylethoxysilane(3-Glycidyloxypropyl)trimethoxysilane, Allyltrimethoxysilane,Allyltriethoxysilane. In another embodiment the silicone moieties aremixed with silicates in a molar ratio silicone:silicate in the range of0.001 to 0.99, optionally 0.01 to 0.90, optionally 0.02 to 0.8,optionally 0.03 to 0.7, optionally 0.05 to 0.6, optionally 0.07 to 0.5,optionally 0.1 to 0.4, optionally 0.05 to 0.30, optionally 0.1 to 0.2.

The polymer of the invention may also be a naturally occurring polymer,such as a naturally occurring polysaccharide. The polysaccharide may beselected from one or more of chitosanate, carrageenanate, alginate,pectinate, xanthan gum, gum Arabic and dextran.

Alternatively, the polymer of the invention may be a synthetic polymer.Such synthetic polymers include derivatized naturally occurringpolysaccharide, such as those selected from one or more of dextransulphate, carboxymethyl dextran, carboxymethylcellulose (CMC),carboxymethyl starch, cellulose sulphate, starch sulphate, cellulosephosphate, cellulose phosphonate, starch phosphate, starch phosphonate.The synthetic polymer may also be one or more of polyacrylic acids(PAA), polymethacrylic acids (PMAA) and polyvinylsulfonic acids (PVS),silicones, and derivatives hereof.

One embodiment of the present invention relates to a method as describedherein, which after step b) of the methods of the present inventionscomprises the steps of;

-   -   c) contacting the remaining aqueous phase with a mobile        solubilized ligand at physico-chemical conditions allowing        formation of a complex between the ligand and the compounds        selected from one or more of PA, PI, LipO and PPO;    -   d) allowing the complex to separate from the aqueous supernatant        phase, optionally by changing said physico-chemical conditions        in the composition to reduce the solubility of the complex; and    -   e) isolating the complex separated from the aqueous phase.

In one embodiment of the invention the PI isolated in step d) of themethods of the present invention contains less than 0.30 g PA per PI,such as less than 0.20 g PA, such as less than 0.15 g PA, such as lessthan 0.10 g PA per g PI.

In one embodiment of the invention the PI isolated in step d) of themethods of the present invention contains less than 200 ppm solanine,such as less than 100 ppm solanine such as less than 70 ppm solanine,such as less than 50 ppm solanine, such as less than 25 ppm solanine,such as less than 10 ppm solanine on a dry matter basis.

In one embodiment of the invention the PI isolated in step d) of themethods of the present invention has a purity (N×6.25) corresponding toat least 70%, such as at least 75%, such as at least 80%, such as atleast 85%, such as at least 90% PI on a dry matter basis.

In one embodiment of the invention the PI isolated in step d) of themethods of the present invention constitutes more than 75%, such as morethan 80%, such as more than 85%, such as, more than 90%, such as morethan 95% of the PI present in the aqueous phase of step a).

In one embodiment of the invention the PI isolated in step d) of themethods of the present invention contains less than 25%, such as lessthan 15%, such as less than 10%, such as less than 5%, such as less than2% of the polyphenoloxidase activity present in the aqueous phaseprovided in step a) on a dry matter basis.

Immobilized Carriers

In several embodiments, the method of the invention also comprises astep of adsorbing and/or binding compounds selected from one or more ofPA, PI, LipO, PPO, glycoalkaloid and phenolic compounds to a solidimmobilized carrier. Such carrier would preferably comprise a porouscross-linked polymer comprising or derivatised with a ligand. Thepolymer with ligand which is cross linked is preferably selected amongthe above mentions polymers and ligands. The cross-linking may becovalent or non-covalent and for cross-linking the polymer one or moreof the abundant well known standard methods for cross-linking may beapplied, such as those described in “Methods for affinity-basedseparations of enzymes and proteins, pp 112-123 Ed.: M. N. Gupta.Springer, Basel 2002”

The solid immobilized carrier may be applied in the form of a powdercapable of being packed in a chromatographic column or it may be formedinto solid beads. The step of binding compounds to the solid immobilizedcarrier may comprise allowing an aqueous solution of the compounds topass the pores of the carrier at conditions allowing the ligand to bindone or more of the compounds.

In a specific embodiment, the immobilized carrier at the selectedconditions adsorbs more PI than compounds selected from one or more ofPA, LipO and PPO. In another embodiment, the carrier at the selectedconditions adsorbs more PA than compounds selected from one or more ofPI, LipO and PPO. In a further embodiment, the carrier at the selectedconditions adsorbs more PPO and LipO than compounds selected from one ormore of PA an PI. In a further embodiment, the carrier at the selectedconditions adsorbs more compounds selected from one or more of PI, LipOand PPO than PA. In a further embodiment, the carrier at the selectedconditions adsorbs more compounds selected from one or more of PI and PAthan PPO and LipO. In a further embodiment, the carrier at the selectedconditions adsorbs more compounds selected from one or more of PPO, LipOand PA than PI. In a further embodiment, the carrier at the selectedconditions adsorbs more compounds selected from one or more ofglycoalkaloid and phenolic compounds than compounds selected from one ormore of PPO, PA, LipO and PI. Such carriers (adsorbents) may suitably bymade of porous synthetic polymers and may be hydrophobic in nature. Inone embodiment of the invention the porous synthetic polymer is ahydrophobic adsorbent comprising a cross-linked aromatic backbone suchas a cross-linked vinyl benzene backbone. In one embodiment of theinvention the porous adsorbent is a Dowex, Lewatit or Amberliteadsorbent.

Complex Formation Between Compound(s) and Ligand(s)

In the method of the invention the ligand will bind to the compound in acondition dependent manner, so that the choice of ligand and conditionschosen in the aqueous phase will determine which compound(s) are boundand in which ratios.

One important condition is the pH of the aqueous phase, and accordinglythe complex formation between the ligand and the compound selected fromone or more of PA, PI, LipO, PPO, glycoalkaloid and phenolic compoundsis carried out in aqueous phase at pH 8 or less, such as pH 7 or less,optionally at pH 6 or less, optionally at pH 5.0 or less, optionally pHat 4.6, optionally pH at 4.5 or less, at pH 2 or more, optionally at pH3 or more, optionally at pH between 3.5 to 4, optionally at pH between 5to 6. optionally at pH between 5.5 to 8.0, such as pH between 6 to 7.

Higher pH values are useful when applying silicon containing polymers,which binds proteins at a higher pH.

Another important condition is the conductivity and/or the ionicstrength of the aqueous solution and accordingly the complex formationbetween the ligand and the compound selected from one or more of PA, PI,LipO, PPO, glycoalkaloid and phenolic compounds is carried out inaqueous phase having a conductivity of at least 5 mS/cm, optionally atleast 7 mS/cm, optionally at least 9 mS/cm, optionally at least 10mS/cm, optionally at least 12 mS/cm, optionally between 5-20 mS/cm,optionally between 8-15 mS/cm, optionally between 9-13 mS/cm.

A further important condition is the temperature of the aqueous phaseand accordingly the complex formation between the ligand and thecompound selected from one or more of PA, PI, LipO, PPO, glycoalkaloidand phenolic compounds is carried out in aqueous phase having atemperature of between 4° C. to 50° C., optionally between 10° C. to 45°C., optionally between 12° C. to 40° C., optionally between 15° C. to35° C.

A still further important condition is the concentration of the mobilesolubilized ligand in the aqueous phase and accordingly the complexformation between the ligand and the compound selected from one or moreof PA, PI, LipO, PPO, glycoalkaloid and phenolic compounds is carriedout in aqueous phase having a polymer concentration between 0.1 to 50g/L, optionally between 0.2 to 20 g/L, optionally between 0.2 to 5 g/L,optionally between 0.2 to 3 g/L, optionally between 0.2 to 2 g/L,optionally between 0.5 to 3 g/L optionally between 0.5 to 2 g/L,optionally between 1.0 to 10 g/L, optionally between 1.0 to 5 g/L,optionally between 1.0 to 3 g/L.

A further important condition is the protein concentration in theaqueous phase and accordingly the complex formation between the ligandand the compound selected from one or more of PA, PI, LipO and PPO iscarried out in aqueous phase having a protein concentrationcorresponding to the sum of PA, PI, LipO and PPO of at least 2 g/L g/L.optionally at least 4 g/L, optionally at least 7 g/L, optionally atleast 8 g/L, optionally at least 9 g/L, optionally between 2 to 22 g/L,optionally between 3 to 20 g/L, optionally between 5 to 15 g/L,optionally between 6 to 12 g/L, optionally between 7 to 11 g/L.

Following these conditions, in an embodiment, the complex formed betweenthe mobile solubilized ligand and the compound selected from one or moreof PA, PI, LipO and PPO comprise between 0.01 mg to 0.5 mg, optionally0.03 mg to 0.3 mg, optionally 0.05 mg to 0.3 mg complexed polymer per mgcomplexed protein. In a further embodiment, the complex formed betweenthe mobile solubilized ligand and the compound selected from one or moreof PA, PI, LipO and PPO comprise between optionally 1 mg to 30 mgcomplexed polymer per mg complexed protein, such as between 2 mg to 25mg, such as between 4 mg to 20 mg, such as between 6 mg to 16 mg, suchas between 7 mg to 15 mg.

Separation of Compound-Mobile Solubilized Ligand Complex fromSupernatant

When the complex between the mobile solubilized ligand and compound isformed, the complex is separated and/or isolated from the aqueous phaseand this separation is preferably achieved by changing thephysico-chemical conditions in the aqueous phase to reduce thesolubility of the complex in the aqueous phase, preferably so that thecomplex solidifies of precipitates from the aqueous supernatant.

In an embodiment, the changing of the physico-chemical conditionscomprises adjusting the pH, optionally to between 2 to 6, optionally tobetween 3 to 6, optionally between 3.5 to 5.5, optionally between 4.0 to5.0. In a particular embodiment, the changing of the physico-chemicalconditions comprises adjusting the pH to between 3.5 to 4. In anotherembodiment, the changing of the physico-chemical conditions comprisesadjusting the pH to between 5 to 6. In a still further embodiment thechanging of the physico-chemical conditions comprises adjusting the pHto between 5 to 9, such as between 5.5 to 8.0, such as between 5.8 to7.5.

In a further embodiment, the changing of the physico-chemical conditionscomprises adjusting the conductivity and/or the ionic strength, forexample by adding salts such as sodium chloride or calcium chloride.

In a further embodiment, the changing of the physico-chemical conditionscomprises adding an organic solvent, such as ethanol.

In a further embodiment, the changing of the physico-chemical conditionscomprises adjusting the temperature.

In a further embodiment, the changing of the physico-chemical conditionscomprises a combination of one or more of adjusting pH, adjustingconductivity, adjusting the temperature and adding organic solvent.

When the complex between the mobile solubilized ligand(s) and thecompound(s) has separated from the aqueous supernatant by precipitation,the precipitated complex is separated from the aqueous supernatant phasepreferably by a mechanical separation process selected from one or moreof membrane separation and centrifugal separation.

The membrane separation process is in one embodiment a continuousmembrane separation process, such as a cross flow, a dynamic or atangential flow membrane separation process. Such membrane separationmethods are well known to the skilled person. Suitable membraneseparation processes include but is not limited to employing a membranemodule selected from one or more of tubular membranes, hollow fibremembranes, spiral wound membranes and plate and frame membranes.Suitable membrane materials for such membrane modules include but is notlimited to one or more of ceramics, metal, synthetic polymers andnatural polymers. In an embodiment, the membrane is a polyether sulfonemembrane or an esterified cellulose membrane. In another embodiment, themembrane process is a filtration process such as a dead-end filtrationprocess.

When employing a membrane module with a hollow fibre membrane theseparation process is preferably performed at the following conditions:

pH of the aqueous phase of between 2 to 6.

Feed pressure of between 9 to 15 psi

Backwash pressure of between 9 to 15 psi.

Temperature of the aqueous phase of between 5° C. to 30° C.

When employing a membrane module with a spiral wound membrane theseparation process is preferably performed at the following conditions:

pH of the aqueous phase of between 2 to 6.

Feed pressure of less than 120 psi

Backwash pressure of between 20 to 40 psi.

Temperature of the aqueous phase of between 5° C. to 45° C.

When employing a membrane module with a ceramic tubular membrane theseparation process is preferably performed at the following conditions:

pH of the aqueous phase of between 3 to 7.

Feed pressure of 60 to 100 psi

Backwash pressure of between 10 to 30 psi.

Temperature of the aqueous phase of between 5° C. to 40° C.

Once the precipitated complex has been retained from aqueous supernatantby the membrane is may be subjected to a diafiltration step by addingfurther solvent to the feed stream.

The centrifugal separation process involves in an embodiment acentrifuge and/or a liquid cyclone separator. The centrifugalacceleration employed is preferably between 500 to 5000 G, optionallybetween 1000 to 4000 G, optionally between 1500 to 3000 G and thecentrifugal separation process is preferably a continuous process,optionally having a retention time of less than 30 min, optionally lessthan 15 min, optionally less than 10 min, optionally less than 5 min,optionally less than 3 min, optionally less than 2 min. The centrifugeof liquid cyclone separator preferably is designed to have a flow ratecapacity of more than 50 L/min, optionally more than 100 L/min,optionally more than 200 L/min, optionally more than 300 L/min,optionally more than 400 L/min, optionally more than 500 L/min,optionally between 50 to 1000 L/min, optionally between 100-750 L/min,optionally between 75 to 400 L/min.

Where the centrifugal separation process involves a liquid cycloneseparator, the liquid cyclone separator is preferably a multistageseparator comprising at least two serial hydrocyclones, optionally atleast three serial hydrocyclones, optionally at least four serialhydrocyclones.

Cyclonic separation is a method of removing particulates from an air,gas or liquid stream, without the use of filters, through vortexseparation. When removing particulate matter from liquids, ahydrocyclone is used. Rotational effects and gravity are used toseparate mixtures of solids and fluids. A high-speed rotating liquidflow is established within a cylindrical or conical container called acyclone. Flows in a helical pattern, beginning at the top (wide end) ofthe cyclone and ending at the bottom (narrow) end before exiting thecyclone in a straight stream through the center of the cyclone and outthe top. Larger (denser) particles in the rotating stream have too muchinertia to follow the tight curve of the stream, and strike the outsidewall, then drop to the bottom of the cyclone where they can be removed.In a conical system, as the rotating flow moves towards the narrow endof the cyclone, the rotational radius of the stream is reduced, thusseparating smaller and smaller particles.

In a further embodiment, the mechanical separation method is capable ofretaining compounds having a size of more than 50 kDa, optionally havinga size of more than 75 kDa, optionally having a size of more than 100kDa, optionally having a size of more than 125 kDa, optionally having asize of more than 150 kDa.

Redissolution of Precipitated Complex

When the precipitated complex has been separated from the aqueoussupernatant, the compound(s) in the complex may advantageously befurther purified and/or separated by mixing the precipitated complexwith a substance capable of extracting one or more compounds selectedfrom PA, PI, LipO, PPO, glycoalkaloid and phenolic compounds from thecomplex and isolating the one or more compounds selected from PA, PI,LipO, PPO, glycoalkaloid and phenolic compounds by a mechanicalseparation process concentrating the one or more compounds selected fromPA, PI, LipO, PPO, glycoalkaloid and phenolic compounds in theretentate.

In a preferred embodiment, the substance is an aqueous solvent,optionally having, an increased pH and optionally an increasedconductivity and/or ionic strength compared to the aqueous supernatantphase from which the complex separated.

In a specific embodiment, the aqueous solvent has a pH between 7 to 14and optionally a conductivity between 10 mS/cm to 200 mS/cm. In afurther embodiment to avoid cost of chemicals and waste effluenttreatments the aqueous solvent has a conductivity 0.1 mS/cm and 10mS/cm.

The substance may also be a solid substance increasing the pH in theisolated complex. Such solid substances include but is not limited tosolid substance is selected from one or more of oxides, hydroxides,phosphates, carboxylates and ammonia, optionally in the form of salts ofammonium or metals, such as sodium, potassium, calcium, magnesium.

The mechanical separation process concentrating the one or morecompounds selected from PA, PI, LipO, PPO, glycoalkaloid and phenoliccompounds in the retentate, may be selected from the membrane separationand centrifugal separation processes described, supra.

Selective Elution of Undesired Compounds

When the precipitated complex has been isolated/separated from theaqueous supernatant, the compound(s) in the complex may advantageouslybe further purified and/or separated by incorporating a step ofselective elution. The selective elution step releases one or morecompounds associated with the isolated complex, compounds which aretypically entrapped in the solid complex matrix or bound to a moiety ofthe ligand or the complexed compound or comprised in liquid remaining inthe complex. Besides impurities from the plant juice the elutedcompound(s) may be selected from one or more of glycoalkaloid, phenoliccompounds, PPO, PA, LipO, PI and the ligand. In an embodiment, theeluted compound(s) may be selected form one or more of glycoalkaloid,LipO, phenolic compounds, PPO and the ligand. In a further embodiment,the eluted compound(s) may be selected form one or more of PA and PI.

In a further embodiment, the eluted compound(s) may be selected from oneor more of PPO, PA and PI.

The selective elution is preferably performed by contacting the isolatedcomplex with a solvent which releases the compound and the solvent ispreferably an aqueous solvent, optionally wherein conditions areselected from pH 1 to pH 6, optionally from pH 6 to 9, optionally frompH 6.5-8.5, optionally from pH 7 to 8 and a conductivity between 1 mS/cmto 300 mS/cm optionally from pH 2 and a conductivity between 10 mS/cm to200 mS/cm, optionally from pH 3 to pH 4.5 and a conductivity between 50mS/cm and 100 mS/cm, optionally from pH 4.6 to pH 5 and a conductivitybetween 25 mS/cm to 250 mS/cm. Carefully selecting these conditionsinfluences which compounds are eluted and in which amounts. The solventmay also comprise or consist of an organic solvent, optionally selectedfrom one or more of alcohols, glycols, esters, ethers, amines, aromaticacids, alkyl acids such as methanol, ethanol, propanol, polyethyleneglycol, (PEG), propylene glycol (PG), monopropylene glycol (MPG),glycerol, benzoic acid, hexanoic acid, octanoic acid and derivatives ofthese. The solvent may further comprise a surfactant, preferablyselected from one or more of non-ionic surfactants, anionic surfactants,cationic surfactants, zwitterionic or amphoteric surfactants. Examplesof useful surfactants are Sodium Dodecyl Sulphate, Tween 20 and cetyltrimethyl ammonium bromide. In one embodiment, the eluted compound is PIand the solvent is an aqueous solution of sodium chloride at aconcentration between 0.2 M to 2 M, optionally a concentration between0.3 M to 1 M, optionally a concentration between 0.4 M to 0.8 M,optionally a concentration between 0.45 M to 0.65 M. In a furtherembodiment the aqueous solvent further comprises a buffer having a pHbetween pH 1 to pH 4.5, optimally a pH between 2 to pH 4.0, optionally apH between pH 2.5 to pH 3.6. In a further embodiment, the aqueoussolvent comprises a salt, optionally selected from alkali or earthalkali metal salts of chloride, nitrate, nitrite sulphate, sulphite,phosphate, acetate or citrate.

Further Method Steps

The isolated compound(s) selected from one or more of PA, PI, LipO, PPO,glycoalkaloid and phenolic compounds may be subjected to furtherprocessing steps for preparing a finished product applicable to adesired use.

In one embodiment, the isolated compound(s), whether in solid ordissolved form, is subjected to a microbial control step. This microcontrol step may comprise adding an agent to the compound(s) selectedfrom one or more of bactericidal agents, bacteriostatic agent,fungicidal agents and fungistatic agents. An addition or alternativelythe microbial control step may also comprise operations selected fromone or more of heating, irradiating and filtering.

The isolated compound(s) may still be bound to the ligand and the ligandmay in some applications provide additional functionality, while inother applications being unwanted. Accordingly, in one embodiment, themethod of the invention further comprises a step of separating the oneor more of PA, PI, LipO, PPO, glycoalkaloid and phenolic compounds fromthe ligand.

The isolated compound(s) may also still possess certain properties,which in some applications may be unwanted, for example enzymesactivity. Accordingly, in an embodiment the method of the inventionfurther comprises a step of inactivating the one or more of PA, PI, LipOand PPO, optionally irreversibly inactivating the said compounds. Suchinactivation may for example be achieved by denaturation, such asthermal or solvent denaturation.

The isolated compound(s) may also be processed into a formulation whichis suitable for its use and its distribution. The form may also bebeneficial for its stability and/or shelf life. Accordingly, in anembodiment the method of the invention comprises forming the isolatedcompound(s) complex into a formulation selected from powders, pastes,slurries or liquids. The powder may in a preferred embodiment be madefrom known methods including drying, spray drying, spray cooling orprilling, (fluid bed) coating, extrusion, mixer granulation, coreabsorption, lyophilization, flash freezing, microgranulation,encapsulation or microencapsulation.

If the formulation form is a liquid, it is considered important for thestability to keep the water activity under control, Accordingly, in anembodiment the water activity, aw, of the formulation is below 0.9,optionally below 0.7, optionally below 0.6. The water activity can bereduced by adding a mono- or disaccharide to the formulation, such asmono- or disaccharide is selected from one or more of glucose, fructose,sucrose and lactose. The water activity may also be reduced by adding adextrin derived from starch. For further stabilization, the formulationmay be added stabilizing agents, optionally selected from one or moreantioxidants, reducing agents, PVP, PVA and PEG.

Spray drying is to be understood as when a liquid solution of compoundis atomized in a spray drying tower to form small droplets which duringtheir way down the drying tower dry to form a particulate materialcontaining the compound. Very small particles can be produced this way(Michael S. Showell (editor); Powdered detergents; Surfactant ScienceSeries; 1998; vol. 71; page 140-142; Marcel Dekker).

Coating is to be understood as when wherein the compounds is coated as alayer around a pre-formed inert core particle, wherein a solutioncontaining the compound is atomized, typically in a fluid bed apparatuswherein the pre-formed core particles are fluidized, and the solutionadheres to the core particles and dries up to leave a layer of drycompound on the surface of the core particle. Particles of a desiredsize can be obtained this way if a useful core particle of the desiredsize can be found. This type of product is described in e.g. WO97/23606.

Core absorption is to be understood as when the compound is absorbedonto and/or into the surface of a porous core particle. Such a processis described in WO 97/39116.

Extrusion or pelletation is to be understood as when a paste containingthe compound is pressed to pellets or under pressure is extruded througha small opening and cut into particles which are subsequently dried.Such particles usually have a considerable size because of the materialin which the extrusion opening is made (usually a plate with bore holes)sets a limit on the allowable pressure drop over the extrusion opening.Also, very high extrusion pressures when using a small opening increaseheat generation in the paste, which may be harmful to the compound.(Michael S. Showell (editor); Powdered detergents; Surfactant ScienceSeries; 1998; vol. 71; page 140-142; Marcel Dekker).

Prilling or spray cooling is to be understood as when compound issuspended in molten wax and the suspension is sprayed, e.g. through arotating disk atomiser, into a cooling chamber where the dropletsquickly solidify (Michael S. Showell (editor); Powdered detergents;Surfactant Science Series; 1998; vol. 71; page 140-142; Marcel Dekker).The product obtained is one wherein the compound is uniformlydistributed throughout an inert material instead of being concentratedon its surface. Also U.S. Pat. Nos. 4,016,040 and 4,713,245 aredocuments relating to this technique.

Mixer granulation is to be understood as when a liquid containing thecompound is added to a dry powder composition of conventionalgranulating components. The liquid and the powder in a suitableproportion are mixed and as the moisture of the liquid is absorbed inthe dry powder, the components of the dry powder will start to adhereand agglomerate and particles will build up, forming granulatescomprising the compound. Such a process is described in U.S. Pat. No.4,106,991 (NOVO NORDISK) and related documents EP 170360 B1 (NOVONORDISK), EP 304332 B1 (NOVO NORDISK), EP 304331 (NOVO NORDISK), WO90/09440 (NOVO NORDISK) and WO 90/09428 (NOVO NORDISK). In a particularproduct of this process wherein various high-shear mixers can be used asgranulators, granulates consisting of the compound, fillers and bindersetc. are mixed with cellulose fibers to reinforce the particles.

Unit Operations for Carrying Out the Method of the Invention

The method of the invention is very applicable to industrial scaleprocesses of plant materials. Accordingly, the formation of the complexin the aqueous phase is preferably carried out in a reactor having avolume of at least 500 L, optionally at least 1000 L, optionally atleast 4000 L, optionally at least 8000 L optionally at least 15000 Loptionally at least 25000 L, said reactor optionally equipped with meansfor thermal control and agitation. In an embodiment, the reactor is acontinuous reactor or a batch reactor. The means for agitation mayinclude stirring, shaking, rotation, vibrating or pumping, while themeans for thermal control may involve heating sources selected fromsteam, electricity and fuel and cooling sources from liquid or gascooling.

PH Adjustment and Precipitation

As disclosed in the Examples, one way of carrying out the presentinvention may be as described in Example 32. Thus, the present inventionrelates to e.g. how to isolate a PA enriched fraction with pH adjustmentfrom pretreated potato juice (with water glass). This show that anaqueous phase comprising compounds selected from two or more of PA, PI,PPO, LipO, pectin, lipid, glycoalkaloid and phenolic compounds of whichat least one compound is selected from PA, PI, LipO and PPO with a trueprotein concentration for example 11 g/L can be pre-treated by additionof a water glass solution followed by incubation. The sample may then becentrifuged and the supernatant collected.

The precipitate may then be washed by resuspension in water pH adjustedto 3.0 with hydrochloric acid and repeated centrifugation (precipitate1). The precipitate may then be then suspended in water and pH may thenbe slowly adjusted to pH 9 with 1 M NaOH during mixing at ambienttemperature.

The SDS-PAGE of FIG. 22 illustrates that the supernatant from the pHprecipitation (see lane 3) contains only a very small fraction of the PAcompared to the starting material. The major part of PI is still insolution resulting in a highly enriched PI fraction (see lane 3, strongPI bands). The dissolved precipitate contains PA and only aninsignificant fraction of PI resulting in a highly enriched PA product,see lane 4. The low turbidity of test solution 3 (containing thenon-precipitated PI fraction) is highly advantageous for furtherprocessing e.g. by membrane filtration or an additional precipitationstep.

When compared to a corresponding dissolved precipitate containing PAfrom a potato juice that is not pre-treated according to the invention,test solution 4 would have significantly better re-solubilizationcharacteristics and a lower turbidity.

In one embodiment of the invention the aqueous phase in step b) isadjusted to a pH below pH 5.5, such as below pH 5.0, such as below pH4.5, such as below pH 4.0

In one embodiment of the invention the aqueous phase in step b) isadjusted to a pH in the range of pH 1-5.5, such as in the range of pH1.5-5.0, such as in the range of 2.0-4.5, such as in the range of pH2.0-3.8, such as in the range of pH 2.5-3.5.

In certain product applications, it is of interest to separatelipoxygenase from PI without completely separating PA from PI. Thus, inone embodiment of the invention the aqueous phase in step b) is adjustedto a pH in the range of pH 3.0-5.0, such as in the range of pH 3.0-4.5,such as in the range of pH 3.3-4.2, whereby Lipoxygenase in theresulting precipitate is separated from PI in the remaining aqueousphase.

An aspect of the present invention relates to a method for isolating afirst group of compounds selected from one or more of patatin protein(PA), protease inhibitor protein (PI), lipoxygenase (LipO) andpolyphenol oxidase (PPO) from a second group of compounds selected fromone or more of PA, PI, LipO, PPO, pectin, lipid, glycoalkaloid andphenolic compounds said method comprising

a) providing an aqueous phase comprising compounds selected from two ormore of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid and phenoliccompounds of which at least one compound is selected from PA, PI, LipOand PPO;

b) performing one or more steps to reduce the concentration of solaninein the dry matter of the aqueous phase with at least 5 percent and toachieve an optical density at 620 nm of the remaining aqueous phase ofless than 0.7;

c) adjusting pH of the remaining aqueous phase (from step b)) to allowthe formation of a precipitate comprising PA; and

d) isolating the precipitate from the aqueous phase.

An aspect of the present invention relates to a method as describedherein, which method after step b) comprises the steps of;

-   -   f) adjusting pH of the remaining aqueous phase (from step b)) to        allow the formation of a precipitate comprising PA;    -   g) isolating the precipitate from the aqueous phase.

In one embodiment of the invention the pH of the aqueous phase in stepb) is adjusted to a pH in the range of 5-9.

In one embodiment of the invention the isolated precipitate in step c)is dissolved by adjusting pH to a pH above pH 5 such as a pH above pH 6,such as a pH above 7 such as a pH in the range of pH 5-10, such as a pHin the range of 6-9, such as a pH in the range of pH 6.5-8.5.

In one embodiment, the invention relates to a method, wherein the pH ofthe aqueous phase in step b) is adjusted to a pH in the range of 5-9,preferably in the range of 6-8.

In one embodiment, the dissolved precipitate is treated to furtherincrease the purity of the PA.

In one embodiment, the dissolved precipitate is clarified bycentrifugation and/or filtration.

In one embodiment the dissolved precipitate is re-precipitated bychanging pH.

This may be repeated several times as part of a washing process toachieve a higher purity of PA.

In one embodiment, the dissolved precipitate is added a soluble silicateand pH adjusted (if necessary) to achieve the precipitation of unwantedimpurities.

In one embodiment, the dissolved precipitate is added a divalent ortrivalent metal ion and pH adjusted (if necessary) to achieve theprecipitation of unwanted impurities.

In one embodiment, the dissolved precipitate is treated with a solidphase adsorbent to adsorb unwanted impurities.

In one embodiment, the dissolved precipitate is treated with a solidphase adsorbent to adsorb glycoalkaloids and/or phenolic compounds.

In one embodiment, the dissolved precipitate is subjected to a membranefiltration process to separate PA in the retentate from unwantedimpurities in the permeate

In one embodiment, the membrane filtration process is a tangential flowultrafiltration process employing a membrane having a nominal pore sizein the range of approx. 10.000-200.000 kDa, such as in the range ofapprox. 30.000-150.000 kDa, such as in the range of approx.50.000-100.000 kDa

In one embodiment of the invention the isolation of PI in step d) of themethods of the present invention above comprise subjecting the remainingaqueous phase to a solid phase adsorption step thereby adsorbing the PIand separating it from the aqueous phase.

In one embodiment of the invention the solid phase adsorption isperformed using an adsorbent having negatively charged ligands such asion exchanging ligands including carboxylic acid, sulfonic acid andphosphonic acid ligands.

In one embodiment of the invention the solid phase adsorption isperformed using an adsorbent having aromatic acid ligands attachedthereto.

In one embodiment of the invention the solid phase adsorbent comprises abenzoic acid, a carboxymethyl benzene, a benzene sulfonic acid or a(sulfomethyl) benzene ligand or derivatives hereof.

In one embodiment of the invention the isolation of PI in step d) of themethods of the present invention above comprise subjecting the remainingaqueous phase to a membrane filtration process separating PI in theretentate from at least one of lipid, glycoalkaloid and phenoliccompounds in the permeate.

In one embodiment of the invention said membrane filtration process is atangential flow ultrafiltration process.

In one embodiment of the invention said ultrafiltration process isperformed using a membrane having a nominal pore size (cut-off value) ofless than 50.000 D, such as less than 30.000 D. In one embodiment, themembrane has a nominal pore size of about 10.000 D.

In one embodiment of the invention the ultrafiltration process isperformed at a pH value in the range of pH 1-6, such as pH 1.5-5.0, suchas pH 2.0-4.5, such as pH 2.5-4.0 such as pH 3.0-4.0, such as pH1.5-2.5.

In one embodiment of the invention the ultrafiltration process isperformed at a pH value in the range of pH 0.1-1.0, such as pH 0.5-0.9,

In one embodiment of the invention the isolation of PI in step d) of themethods of the present invention above comprise subjecting the remainingaqueous phase to a solid phase adsorption step thereby adsorbingglycoalkaloids and phenolic compounds and separating it from the aqueousphase.

In one embodiment of the invention the isolation of PI in step d) of themethods of the present invention comprise subjecting the PI retentateafter the ultration process to a solid phase adsorption step therebyadsorbing glycoalkaloids and phenolic compounds and separating it fromthe PI retentate.

In one embodiment of the invention the solid phase adsorption isperformed by contacting the remaining aqueous phase or the PI retentatewith a solid phase adsorbent selected from the group of activatedcarbon, layered silicate adsorbents and porous synthetic polymers.

In one embodiment of the invention the porous synthetic polymer is ahydrophobic adsorbent

In one embodiment of the invention the porous synthetic polymer is ahydrophobic adsorbent comprising a cross-linked aromatic backbone suchas a cross-linked vinyl benzene backbone.

In one embodiment of the invention the porous synthetic polymer is aDowex, Lewatit or Amberlite adsorbent.

In one embodiment of the invention the isolation of PI in step d) of themethods of the present invention above comprise subjecting the remainingaqueous phase to a precipitation step thereby precipitating the PI andseparating it from the aqueous phase.

In one embodiment of the invention said precipitation step comprise theaddition of a precipitation agent to the remaining aqueous phase.

In one embodiment of the invention said precipitation agent comprise oneor more compounds selected from lyotropic salts, anionic polymers,silicates, polyphosphates, organic solvents.

In one embodiment of the invention said precipitation is performed at apH in the range of 0.1-5.0, such as a pH in the range of 0.7-4.9, suchas a pH in the range of 1.0-4.5, such as a pH in the range of 1.5-4.0,such as a pH in the range of 1.9-3.6, such as a pH in the range of2.5-3.5, such as a pH in the range of 3.5-4.5.

Membrane Filtration

An aspect of the present invention relates to a method for isolating afirst group of compounds selected from one or more of patatin protein(PA), protease inhibitor protein (PI), lipoxygenase (LipO) andpolyphenol oxidase (PPO) from a second group of compounds selected fromone or more of PA, PI, LipO, PPO, pectin, lipid, glycoalkaloid andphenolic compounds said method comprising

a) providing an aqueous phase comprising compounds selected from two ormore of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid and phenoliccompounds of which at least one compound is selected from PA, PI, LipOand PPO;

b) performing one or more steps to reduce the concentration of solaninein the dry matter of the aqueous phase with at least 5 percent and toachieve an optical density at 620 nm of the remaining aqueous phase ofless than 0.7; and

c) subjecting the remaining aqueous phase (from step b) of the methodsof the present invention) to a membrane filtration process separating atleast one of PA and PI in the retentate from at least one of PA, PI,LipO, PPO, pectin, lipid, glycoalkaloid and phenolic compounds in thepermeate.

In one embodiment of the present invention is the concentration ofsolanine in the dry matter of the aqueous phase reduced with at least10%, such as at least 20%. The reduction may be at least 25%.

An aspect of the present invention relates to a method as describedherein, which method after step b) comprises the step of;

-   -   h) subjecting the remaining aqueous phase (from step b) of the        methods of the present invention) to a membrane filtration        process separating at least one of PA and PI in the retentate        from at least one of PA, PI, LipO, PPO, pectin, lipid,        glycoalkaloid and phenolic compounds in the permeate.

Aqueous Phase and Plant Material

The aqueous phase of the invention is typically a crude fraction orstream from industrial processing of plant materials. It may beundiluted aqueous juices directly obtained from shredding, crushing,squeezing and/or pressurizing plant materials or it may also result fromadding an aqueous solvent to the plant material and extracting watersoluble compound therefrom. To avoid generating excess waste water themethod of the invention is advantageously capable of employing undilutedplant juices directly obtained from and released from disintegrating theplant material. The plant material can be any plant material comprisingthe compounds of the invention, such as the tuber portion of a plant ofthe genus Solanum, in particular the species S. tuberosum (potato).Accordingly, in an embodiment the aqueous phase of the inventioncomprise an aqueous solution liberated when disintegrating a portion ofa plant optionally a tuber portion of a plant of the genus Solanum,optionally of the species S. tuberosum. In another embodiment, theaqueous phase of the invention consists of an aqueous solution liberatedwhen disintegrating a portion of a plant optionally a tuber portion of aplant of the genus Solanum, optionally of the species S. tuberosum. In afurther embodiment the aqueous phase of the invention comprise theaqueous solution liberated when disintegrating the plant materialdiluted with less than 50 wt % added solvent, optionally less than 25 wt% added solvent, optionally less than 20 wt % added solvent, optionallyless than 15 wt % added solvent, optionally less than 10 wt % addedsolvent, optionally less than 5 wt % added solvent, optionally less than2 wt % added solvent, optionally less than 1 wt % added solvent.

The aqueous phase of the invention comprises in an embodiment at least 3grams protein per litre, optionally at least 5 g/L, optionally at least8 g/L, optionally at least 10 g/L, optionally at least 12 g/L,optionally between 5 to 25 g/L, optionally between 6 to 20 g/L,optionally between 7 to 15 g/L, optionally between 8 to 12 g/L,optionally between 9 to 11 g/L.

In an embodiment of the invention 30 to 50% of the protein in theaqueous phase is PA, while in another embodiment 30 to 50% of theprotein in the aqueous phase is PI. Particularly, at least 60% of theprotein in the aqueous phase is PA or PI.

The aqueous phase of the invention further comprises in an embodiment atleast 50 mg/kg of glycoalkaloid, optionally at least 75 mg/kg,optionally at least 100 mg/kg, optionally at least 125 mg/kg, optionallyat least 150 mg/kg, optionally at least 175 mg/kg, optionally at least200 mg/kg, optionally at least 250 mg/kg, optionally at least 300 mg/kg,optionally between 50-400 mg/kg, optionally between 75-350 mg/kg,optionally between 100-300 mg/kg of glycoalkaloid. Further, the aqueousphase of the invention further comprises in an embodiment, at least 10mg/kg of phenolic compound, optionally at least 25 mg/kg, optionally atleast 50 mg/kg, optionally at least 125 mg/kg, optionally at least 170mg/kg, optionally at least 225 mg/kg, optionally at least 300 mg/kg,optionally at least 400 mg/kg, optionally at least 600 mg/kg, optionallybetween 25 to 2000 mg/kg, optionally between 75 to 1500 mg/kg,optionally between 200 to 1000 mg/kg phenolic compounds.

In one embodiment of the invention the aqueous phase in step a) of themethods of the present invention is potato fruit juice obtained fromindustrial manufacture of potato starch.

In one embodiment of the invention the fruit juice is further treated ina defoamer to substantially reduce the amount of foam in the fruitjuice.

In one embodiment of the invention the fruit juice has been treated tosubstantially reduce the amount of insoluble substances in the fruitjuice prior to pH adjustment in step b) of the methods of the presentinvention.

In one embodiment of the invention the fruit juice is pH adjusted by anin-line mixing with an acid.

In one embodiment of the invention the fruit juice has been added anantioxidant, such as sodium bisulfite or sodium sulfite.

In one embodiment, the fruit juice has a total true proteinconcentration of at least 5 g/L such at least 6 g/L, such as at least 7g/L, such as at least 8 g/L fruit juice.

In one embodiment, the aqueous phase is a root or tuber juice, alsoknown herein as fruit juice.

In one embodiment, the juice is potato juice.

One embodiment of the present invention relates to a root or tuberjuice, obtainable by a method according to the present invention,comprising at least 0.5 wt. % of dissolved protein, wherein the proteinis native and wherein the clarity, expressed as OD620, is less than 0.8.

In one embodiment, the root or tuber juice does not comprise an acrylicpolymer.

In industrial processing of plant materials, it is desired to avoidcostly and mechanically complicated steps such as removal of peelingsfrom the inner portions of the plant material. However, peelings maycontain considerable amounts of undesired compounds, such asglycoalkaloid and phenolic compounds, and one advantage of the presentinvention is that the method works surprisingly well also for crudeplant juices. Accordingly, in one embodiment the plant portion isunpeeled before disintegration, and optionally the aqueous solutionincludes juices from plant peelings as well. It may however be desirableafter disintegrating the plant material and before precipitating thecomplex to separate insolubles, such as suspended fibres and inorganicsolids from the plant juice and/or aqueous phase and accordingly in anembodiment the method of the invention further comprises separatinginsoluble solid components, including suspended fibres, of thedisintegrated plant portion from the aqueous solution liberated from theplant material.

Applications of the Methods and Products

The invention also provides a composition comprising the isolated one ormore compounds of patatin protein (PA), protease inhibitor protein (PI),lipoxygenase (LipO) and polyphenol oxidase (PPO), glycoalkaloid andphenolic compounds obtainable from the method of the invention. Thecomposition may also in an embodiment comprise the ligand bound to thecompound(s). Accordingly, the composition may comprise at least 25%,optionally at least 50%, optionally at least 75% of the ligand containedin the complex formed between the compound(s) and the ligand. Preferablythe composition comprises one or more of PA, PI and PPO.

The composition of the invention may be an additive for one or more offoods, animal feeds, pet foods, beverages, cosmetics, pharmaceuticals,nutraceuticals, dietary supplements and fermentations. Additives forfood or beverage include additives for meats, confectionary, bread,dairy, ready-to-eat food, senior nutrition products and sports foods anddrinks. Additives for animal feed includes additives for poultry feed,ruminants feed, pig feed, horse feed, fish feed and insect feed.Additives for pet food include additives for canine or feline pet foods.Additives for cosmetics include additives for lotions, creams, gels,ointments, soaps, shampoos, conditioners, antiperspirants, deodorants,mouth wash, contact lens products and foot bath products. Additives fordietary supplements include additives for protein supplements and seniornutrition products. Additives for fermentations include additives forbacterial, fungal and yeast fermentations.

In further embodiments, the composition of the invention may be selectedfrom one or more of food or beverages, animal feeds, pet foods,cosmetics, pharmaceuticals, nutraceuticals, dietary supplements andfermentation broths.

In an embodiment, the composition is a cosmetic composition comprisingglycoalkaloid, optionally for use as an exfoliant.

In another embodiment, the composition is a pharmaceutical compositioncomprising glycoalkaloid for use as a medicament, preferably amedicament for treating cancer.

Depending on the ligand and the conditions chosen the complex maycomprise different compounds bound to the ligand. In an embodiment, thecompound is a protein and a particularly complex of the invention maycomprise one or more of PA, PI, LipO and PPO.

In one embodiment, the complex comprises, on a dry weight basis, morethan 51.9 wt % PA, optionally more than 55 wt % PA, optionally more than65 wt % PA, optionally more than 75 wt % PA, optionally more than 85 wt% PA, optionally more than 95 wt 15% PA relative to the total amount ofPA, PI, LipO and PPO in the complex. In an alternative embodiment, thecomplex comprises more than 88.6 wt % PA of total PA, optionally morethan 90 wt % PA of total PA, optionally more than 95 wt % PA of totalPA, optionally more than 97 wt % PA of total PA, optionally more than 99wt % PA of total PA.

In another embodiment, the complex comprises, on a dry weight basis,more than 50 wt % PI, optionally more than 55 wt % PI, optionally morethan 65 wt % PI, optionally more than 75 wt % PI, optionally more than85 wt % PI, optionally more than 95 wt % PI relative to the total amountof PA, PI, LipO and PPO in the isolated complex. In an alternativeembodiment, the complex comprises more than 90 wt % PI of total PI,optionally more than 95 wt % PI of total PI, optionally more than 97 wt% PI of total PI, optionally more than 99 wt % PI of total PI.

The complex may also comprise, on a dry weight basis, more than 50 wt %PPO, optionally more than 55 wt % PPO, optionally more than 65 wt % PPO,optionally more than 75 wt % PPO, optionally more than 85 wt % PPO,optionally more than 95 wt % PPO relative to the total amount of PA, PI,LipO and PPO in the isolated complex. In an alternative embodiment, thecomplex comprises more than 90 wt % PPO of total PPO, optionally morethan 95 wt % PPO of total PPO, optionally more than 97 wt % PPO of totalPPO, optionally more than 99 wt % PPO of total PPO.

The complex may also comprise from 60 to 95 wt % PA; and from 0.9 to39.9 wt % PI and from 0.1 to 4.1 wt % PPO relative to the total amountof PA, PI, LipO and PPO in the complex.

The complex may also comprise from 80-99.9 wt % PA of total PA in theaqueous phase; from 0.1 to 20 wt % PI of total PI in the aqueous phaseand from 0.1 to 20 wt % PPO of total PPO in the aqueous phase.

The PA may be complexed to the ligand in a PA:ligand dry weight ratio ofat least 4:1, optionally at least 8:1, optionally at least 10:1,optionally at least 15:1. PI may be complexed to the ligand in aPI:ligand dry weight ratio of at least 3:1, optionally at least 5:1,optionally at least 8:1, optionally at least 10:1. PPO may be complexedto the ligand in a PPO:ligand dry weight ratio of at least 2:1,optionally at least 4:1 optionally at least 7:1

In an embodiment, PA is complexed to the ligand in a PA:ligand dryweight ratio of at least 6:1; the PI is complexed to the ligand in aPI:ligand dry weight ratio of at least 5:1 and the PPO is complexed tothe ligand in a PPO:ligand dry weight ratio of at least 2:1, optionallyin a PA:ligand dry weight ratio of at least 6:1; a PI:ligand dry weightratio of at least 7:1 and a PPO:ligand dry weight ratio of at least 2:1.

Using the method of the invention the complex is enriched in PA over PIcompared to PA and PI originally in the aqueous phase, characterised bythat the PA:PI dry weight ratio in the precipitate is at least 25%higher than the PA:PI dry weight ratio for PA and PI remaining dissolvedin the aqueous supernatant phase, optionally at least 50% higher,optionally at least 75% higher.

Using the method of the invention a significant portion of the PA and PIcan be isolated from the aqueous phase and in an embodiment the sum ofPA and PI remaining dissolved in the aqueous supernatant phase is lessthan 15 wt. % of the total PA and PI, optionally less than 12%,optionally less than 10%, optionally less than 8%, optionally less than6%, optionally less than 5%, optionally less than 4%, optionally lessthan 3%, optionally less than 2%, optionally less than 1%, optionallyless than 0.5%.

The method of the invention may also advantageously separate what insome applications are desired compounds such as PA and PI from undesiredcompounds.

Accordingly, in an embodiment the complex contains less than 200milligram of glycoalkaloid per kilogram dry matter, optionally less than150, optionally less than 110, optionally less than 95 mg, optionallyless than 80, optionally less than 65, optionally less than 45,optionally less than 25, optionally less than 10 milligram glycoalkaloidper kilogram dry matter. Alternatively, at least 50%, optionally atleast 65%, optionally at least 75%, optionally at least 82%, optionallyat least 89%, optionally at least 93% of the glycoalkaloid in theaqueous phase remains in the aqueous supernatant phase afterseparation/precipitation of the complex. In a further embodiment, thecomplex contains less than 300 milligram phenolic compounds per kilogramdry matter. optionally less than 250, optionally less than 200,optionally less than 150, optionally less than 125, optionally less than95, optionally less than 70, optionally less than 35 milligram phenoliccompounds per kilogram dry matter. Alternatively, at least 50%,optionally at least 65%, optionally at least 75%, optionally at least85%, optionally at least 90% of the phenolic compounds in the aqueousphase remains in the aqueous supernatant phase after separation of thecomplex. Particularly, the phenolic compound is chlorogenic acid (CGA).In this context chlorogenic acid is to be understood as being an esterof hydroxycinnamic acid and quinic acid, particularly esters betweencaffeic acid, ferulic acid or p-coumaric acid with quinic acid orcombinations thereof. In an embodiment, the complex comprise, on a dryweight basis, less than 120 mg/kg of chlorogenic acid, optionally lessthan 100 mg/kg CGA, optionally less than 80 mg/kg CGA, optionally lessthan 60 mg/kg CGA, optionally less than 40 mg/kg CGA, optionally lessthan 20 mg/kg CGA, optionally less than 10 mg/kg CGA.

An aspect of the present invention relates to a product obtainable by amethod according to the present invention, for use as a feed material, afood ingredient, or in the food or feed industry.

In some cases, the optimal business model for utilizing potato fruitjuice is the combined production of a PA product not intended for use asa functional protein and a highly functional PI product, rather than theproduction of both a functional PA and a functional PI product.

Thus, in one embodiment the isolated precipitate in step c) of themethods of the present invention contains less than 50%, such as lessthan 40%, such as less than 30%, such as less than 20%, such as lessthan 10% functional PA.

In one embodiment, the isolated precipitate in step c) of the methods ofthe present invention contains less than 50%, such as less than 40%,such as less than 30%, such as less than 20%, such as less than 10% PAbeing soluble by suspension of the precipitate in an aqueous phosphatebuffer at 2% dry matter and at pH 7.0.

In one embodiment of the invention the isolated precipitate in step c)of the methods of the present invention is further treated to produce aprotein powder as a human nutritional food product. In one embodiment,the precipitate is washed with an aqueous solution of an acid and dried.

In one embodiment of the invention the isolated precipitate in step c)of the methods of the present invention is further treated to produce aprotein powder as a functional protein ingredient product for humanconsumption. In one embodiment, the precipitate is washed with anaqueous solution of an acid and dried.

The invention also provides methods of using the composition comprisingthe isolated one or more compounds of PA, PI, LipO, PPO, glycoalkaloidand phenolic compounds obtainable from the method of the invention. PA,PI, LipO, PPO, glycoalkaloid and phenolic compounds have a wide range ofapplications in particular in the food/feed/nutrition and healthindustry, since they may provide one or more functions selected fromfoam control, emulsion control, control of proteolytic activity,nutritional improvement, gelation, solubility improvement, organolepticimprovement, allergenicity reduction, oxidation, exfoliation andtreatment of diseases such as cancer.

The invention also provides packaging means for containing thecompositions of the invention. Accordingly, a container is providedcomprising the composition of the invention.

Ligand Compositions

The invention further provides a polymer having aromatic orheteroaromatic acid ligands covalently attached. The polymer may benatural or synthetic and the polymer is preferably soluble in aqueoussolvent above pH 6 and preferably insoluble below pH 5.9. optionallybelow pH 5.5, optionally below pH 5.0, optionally below pH 4.8,optionally below pH 4.5, optionally below pH 4.2, optionally below pH4.0, optionally below pH 3.5. In an embodiment, the polymer comprises asoluble polysaccharide, such as starch, reacted with a bifunctionalreagent for attachment of ligands. The bifunctional reagent may bechosen from one or more of epichlorohydrin, allyldiglycidyl ether, allylbromide and divinyl sulfone. The aromatic or heteroaromatic acid ispreferably chosen from one or more of hydroxybenzoic acid, aminobenzoicacid, mercaptobenzoic acid and derivatives hereof.

EXAMPLES

Materials & Methods:

Chemicals used in the examples herein e.g. for preparing buffers andsolutions are commercial products of at least reagent grade.

Water used for conducting the experiments is all de-ionized water.

Aqueous Solutions Comprising PA, PI, PPO, Glycoalkaloid and Polyphenol

Potatoes of the variety Folva are obtained from a local supermarket.

The potatoes are washed and their surface are dried off before thepotatoes are shredded with the peel while the liberated liquid (juice)concomitantly is separated from the main mass of insolubles using acommercial juicer (Nutrijuicer PRO) without diluting with water.

10 ml sodium sulphite (10 wt %) per 1000 ml juice is added immediatelyto the juice and the juice is centrifuged for 10 min at 1430 G to removeany remaining large insoluble particles such as fibers and starch.

10 kg of potatoes yields about 4.65 L of centrifuged juice (testsolution 1) with a pH of 6.2 and a conductivity of 10.7 mS/cm, measuredwith a Seven2Go S3 conductivity meter from Mettler Toledo, Switzerland.

Mobile Polymeric Ligand Preparations

a) Sodium alginate is obtained from Sigma Aldrich, USA (cat. no.:W201502). 15 g of sodium alginate is added up to 1 L of water and thealginate is solubilized by magnetic stirring yielding a 1.5 wt % sodiumalginate solution (ligand solution A).

b) Kappa carrageenan is obtained from Sigma Aldrich, USA (cat.no.:C1013). 15 g of kappa carrageenan is added up to 1 L of water and thekappa carrageenan is solubilized by magnetic stirring yielding a 1.5 wt% kappa carrageenan solution (ligand solution B).

c) Iota carrageenan is obtained from Sigma Aldrich, USA (cat.no.: C1138)15 g of iota carrageenan is added up to 1 L of water and the iotacarrageenan is solubilized by magnetic stirring yielding a 1.5 wt % iotacarrageenan solution (ligand solution C)

d) Lambda carrageenan is obtained from Sigma Aldrich, USA (cat.no.:22049). 15 g of lambda carrageenan is added up to 1 L of water and thelambda carrageenan is solubilized by magnetic stirring yielding a 1.5 wt% lambda carrageenan solution (ligand solution D)

e) Polyacrylic acid (PAA₄₅₀) having average MW of 450,000 kDa, isobtained from Sigma Aldrich, USA (cat.no.: 181285). 1.5 g of PAA₄₅₀ isadded up to 100 mL of water and the PAA is solubilized by magneticstirring yielding a 1.5 wt % PAA₄₅₀ solution (ligand solution E).

f) Polyacrylic acid (PAA₁₅), having an average MW of 15,000 kDa and in a35 wt % aqueous solution, is obtained from Sigma Aldrich, USA (cat.no.:416037,). 10 ml of the 35 wt % aqueous solution of PAA₁₅ is diluted with223.3 ml water and mixed by magnetic stirring, yielding of 1.5 wt %PAA₁₅ solution (ligand solution F).

Buffer Solutions

A 10 wt % sodium sulphite buffer solution is prepared by dissolving 10 gof sodium sulphite from Sigma Aldrich USA (cat. No.: 13471) in 100 mLwater. pH was not adjusted. Measured to pH 7.7.

A 0.1 M di-potassium hydrogen phosphate pH 7.0 buffer solution isprepared by dissolving 17.42 g di-potassium hydrogen phosphate fromSigma Aldrich USA (cat.no.: P3786) in 900 ml water followed by adjustingpH to 7.0 with 4 M hydrochloric acid. Finally, water is added to 1 L.

A 0.1 M pyrocatechol in 0.1 M di-potassium hydrogen phosphate pH 7.0(for PPO detection) is prepared by dissolving 11.01 g pyrocatechol fromSigma Aldrich, USA (cat.no.: C9510) in 100 ml 0.1 M di-potassiumhydrogen phosphate pH 7.0

SDS-PAGE Electrophoresis Reagents

a) LDS sample buffer, 4× is obtained from Expedeon, USA (Cat.no.:NXB31010)

b) SDS Run buffer, 20× is obtained from Expedeon, USA (Cat.no.:NXB50500)

c) Precast 4-20% gradient gels are obtained from Expedeon, USA (Cat.no.:NXG42012K)

d) Instant Blue Coomassie staining solution is obtained from Expedeon,USA (Cat.no. ISB1L).

Assays

a) SDS-PAGE Electrophoresis

The samples produced in each example are analyzed using SDS-PAGE gelelectrophoresis showing the protein composition in each sample. TheSDS-PAGE gel electrophoresis is performed using an electrophoresisapparatus and precast 4-20% gradient gels from Expedeon USA (Cat.no.:NXG42012K). The protein samples are mixed with LDS sample buffer andincubated for 10 minutes at 70° C. The samples are applied to a precastgel and proteins are allowed run for one hour at 200 V 90 mA in the SDSRun buffer at non-reduced running conditions. The gel is developed inthe staining solution for three hours and the protein bands areevaluated by visually inspection or analyzed by scanning densitometry toquantify the amount of specific proteins in the test solutions.

b) Dry Matter Determination

A Sartorius moisture analyzer (MA37, Sartorius) is used to determine drymatter in a sample by applying 5-10 mL of a sample to the instrument.The sample is then dried at 110° C. until constant weight and theremaining dry matter is determined and calculated by the instrument.

c) Semi-Quantitative Determination of Polyphenol Oxidase (PPO) Activity.

A sample is mixed with a pyrocathecol solution pH 7.0 at ambienttemperature. If the sample contains PPO the solution changes color fromcolorless to orange within 15 minutes. The color intensity obtainedafter 15-minute incubation at room temperature indicates the amount ofPPO enzyme activity in the sample. A sample with an unknown amount ofenzyme activity may quickly be estimated relative to the activityexpressed by a reference sample (e.g. the starting material) anddilutions hereof by visual inspection.

Procedure:

1.95 ml 0.1 M potassium phosphate pH 7.0

1 ml 0.1 M pyrocatechol in 0.1 M potassium phosphate pH 7.0

50 μl sample

The solution is mixed well and incubated for 15 min at ambienttemperature. After 15 min the color intensity is scored relative to areference sample.

d) Determination of Glycoalkaloids

A HPLC method for determination of glycoalkaloids is applied accordingto Alt, V., Steinhof, R., Lotz, M., Ulber, R., Kasper, C., Scheper, T.Optimization of glycoalkaloid analysis for us in industrial potato fruitjuice downstreaming. Eng. Life Sci. 2005, 5, 562-567.

Alpha-solanine (Sigma Aldrich, USA, cat no.: S3757) is used as areference.

e) Test for Alkaline Colored Phenolic Compounds

A qualitative test for the content of complex phenolic compounds basedon the development of color in alkaline medium. 0.5 ml sample is mixedwith 3 ml 1 M sodium hydroxide and the absorbance at 405 nm isdetermined within one minute from mixing (BK-UV1800 spectrophotometer,Biobase, China). The result is calculated relative to the proteinconcentration in the sample as OD405×7/(mg protein per ml sample).

f) Total True Protein Determination.

Standard amino acid quantification is performed according to EUROPEANPHARMACOPOEIA 5.0 section 2.2.56. AMINO ACID ANALYSIS. Total proteinconcentration is also determined by the method of Kjeldahl using theconversion factor N×6.25. All samples are initially dialyzed againstdemineralised water in dialysis tubing cellulose membrane(Sigma-Aldrich, USA, cat. No.: D9652) to remove any free amino acids andlow molecular weight peptides.

Ultrafiltration

Samples are ultrafiltrated using a system from Spectrum Labs, USA,fitted with KrosFlo TFF system KMOi using hollow fiber ultrafiltrationmembranes. A membrane cut-off value of 10 kDA and 100 kDa and membranearea of 75 cm2 is employed (Spectrum Labs, USA cat.no.: T02-E100-10-N).

Example 1. Preparation of a Soluble Starch Polymer Coupled with a MixedMode Ligand (4-Aminosalicylic Acid)

Soluble potato starch Sigma Aldrich, USA (cat.no.: S2004) is activatedwith AGE, bromine treated and coupled with 4-aminosalicylic acid usingthe following procedure: Activation with AGE: 25 g soluble starch ismixed thoroughly with 50 ml of water followed by addition of 25 ml AGEand 4 ml 30% sodium hydroxide. The solution is then incubated for 7.5hours at 65-70° C. followed by addition of acetic acid to neutralize thehydroxide and stop the reaction. The resulting solution is dialyzed in adialysis tube for two days against water to produce a solution free ofremaining low molecular weight reactants while the allylated starch stayin the dialysis bag. The allylated starch polymer is then treated withbromine water (1% solution) until a red-brown color remains indicatingthat substantially all allyl groups have been brominated. The brominetreated polymer is coupled with 4-aminosalicylic acid by mixing 50 mlactivated starch polymer with 5 g of amino salicylic acid and pH isadjusted to 12 with 5 M sodium hydroxide. The solution is mixed atambient temperature for 24 hours where after the solution is dialyzed ina dialysis hose for two days against several shifts of water to producea solution of ligand derivatized starch without any significant amountof free ligand in solution. Dry matter determination of the finalstarch-ligand solution indicated a final concentration of 9 mg per mlsolution. The amount of 4-aminosalicylic acid ligand per mg starch isestimated by acid base titration to be in the range of 3-7 micromolesligand per mg starch.

Example 2. Preparation of Adsorbent Beads Coupled with a Mixed ModeLigand (4-Aminosalicylic Acid)

6% spherical agarose beads (50-150 μm diameter) from ABT, Spain(cat.no.: A-1060M-X) are crosslinked with 1,4-butanediol diglycidylether (BDDGE) from Sigma Aldrich, USA (cat.no.: 124192, 60%) by mixing450 ml agarose beads with 60 ml BDDGE and 27 ml 50 wt % sodium hydroxidefor 18 hours at ambient temperature followed by washing with 10 L wateron a sintered glass funnel.

The cross-linked beads are then activated with allyl glycidyl ether(AGE) Sigma Aldrich, USA (cat.no.: 32608) by mixing 200 ml cross-linkedbeads with 80 ml AGE and 20 ml 30 wt % sodium hydroxide on a temperaturecontrolled water bath (60-65° C.) for three hours. The activated beadsare then washed thoroughly with 5 L water on a sintered glass filter.The cross linked and activated beads are the suspended in 200 ml waterand added bromine water (1% solution) while mixing until a red-browncolor remains in the mixture indicating that a surplus of bromine hasbeen added. After bromine treatment, the beads are washed thoroughlywith water (2 L) on a sintered glass filter.

The mixed mode ligand 4-aminosalicylic acid, Sigma Aldrich, USA(cat.no.: A79604) is coupled to the bromine treated AGE-beads by mixing20 ml bromine treated beads with 2 g of 4-aminosalicylic acid and 10 mlwater followed by adjustment of pH to pH 12 with 5 M sodium hydroxide.The suspension is mixed 24 hours at ambient temperature. The beads arethen washed thoroughly with water, 0.1 M sodium hydroxide and 0.1 Msodium chloride.

The ligand concentration on the resulting beads is determined to be inthe range of 50-80 micromoles per milliliter sedimented wet beads byacid-base titration.

Example 3. Precipitating the PI Fraction from Potato Juice with a LigandDerivatised Starch Polymer

4 ml of potato juice produced according to materials and methods (trueprotein concentration: 8 g/L) (test solution 1) is mixed with 1 ml of4-aminosalicylic acid starch polymer (prepared according to example 1).The pH in the solution is adjusted to pH 5.5 with 1 M hydrochloric acidunder mixing at ambient temperature for 10 minutes. The precipitatedsolution is then centrifuged for 5 min at 1340 g and the supernatant iscollected (test solution 2).

The test solutions are analyzed by SDS-PAGE as illustrated in FIG. 1 .The PPO activity of the test solutions is further determined accordingto materials and methods and shown in table 1.

The SDS-PAGE illustrates that the major part of PI is precipitated withthe starch polymer modified with 4-aminosalicylic acid resulting in a PAenriched juice, see lane 2 which has a rather faint PI band compared tonon-treated juice of lane 1.

Table 1 showing the PPO activity in test solution 1 and 2.

Samples PPO activity Non-treated potato juice (test solution 1) ++++(dark orange) Test solution 2 + (pale yellow)

The results indicate that the PPO is eliminated efficiently from the PAenriched juice.

Example 4. Isolating PI Fraction from Potato Juice with a Mixed ModeAdsorbent

5 respectively 10 and 15 ml of potato juice samples (test solution 1,produced according to materials and methods, true protein concentration:8 g/L) is adjusted to pH 5.5 with 1 M hydrochloric acid and mixed with 1ml of 4-aminosalicylic acid adsorbent (produced according to example 2).The juice samples are incubated with the adsorbent on a roller mixer for30 min at ambient temperature. After incubation, the samples are set atrest for 30 min to settle the adsorbent. The resulting supernatants(test solution 2, 3 and 4 respectively) are collected and tested bySDS-PAGE according to materials and methods as illustrated in FIG. 2 .Test solutions 1-4 is further tested for PPO activity according tomaterials and methods as illustrated in table 2.

Results:

The SDS-PAGE of FIG. 2 , illustrates that the mixed mode adsorbent bindssubstantially all the PI present in the juice at all threejuice:adsorbent ratios. There is a rather small amount of PI left in thesupernatant with 10 and 15 ml juice, see lane 3 and 4. The PA is notbound by the adsorbent in any significant amount resulting in a juicethat is highly enriched with respect to PA.

Samples PPO activity Non-treated potato juice (test solution 1) ++++(dark orange) Test solution 2 + (pale yellow) Test solution 3 + (paleyellow) Test solution 4 + (pale yellow)

The results indicate that the PPO is eliminated efficiently from all thePA enriched samples.

Example 5. Isolating PI Fraction from Potato Juice with a Mixed ModeAdsorbent Followed by Precipitation of PA with Sodium Alginate

10 ml juice prepared according to materials and methods (test solution1, true protein concentration: 12 g/L) is depleted for PI according toexample 4 by incubation with 1 ml adsorbent (test solution 2).

7 ml of the PI depleted sample is then mixed with 1 ml of ligandsolution A and pH is adjusted to 3.5 with 1 M hydrochloric acid underthorough mixing at ambient temperature. After 10 minutes mixing theprecipitated solution is centrifuged for 10 min at 1340 g. Thesupernatant is removed (test solution 3) and the precipitate is washedby resuspension in water and repeated centrifugation. The precipitate ishereafter dissolved by addition of 7 ml 0.1 M potassium phosphate pH 7.0(test solution 4).

The test solutions are tested by SDS-PAGE as illustrated in FIG. 3 .Test solutions 1 and 4 are tested for glycoalkaloids and alkalinecolored phenols.

Results:

The SDS-PAGE of FIG. 3 illustrates that the PA enriched juice onlycontains a minor fraction of the PI, see lane 2 (rather faint PI bandcompared to non-treated juice). LipO is also eliminated from the PAenriched juice, see lane 2 (LipO band has disappeared). Further it canbe observed that the precipitation of PA with sodium alginate is rathereffective, see lane 3 (very faint bands meaning that most of the proteinis precipitated and thereby removed from the supernatant). The resultingdissolved product, see lane 4, is a highly enriched PA fraction with alow content of PI. Determination of the glycoalkaloid content of testsolution 4 relative to test solution 1 shows that also a significantreduction of this toxic substance is taking place.

Visual inspection of the color intensity of the dissolved PA (testsolution 4) compared to the starting material (test solution 1)indicates that almost all colored substances (phenolic compounds) remainin the juice and very little is found in the re-dissolved PA solution(test solution 4). Likewise, the presence of alkaline colored phenols ismuch lower in test solution 4 compared to test solution 1.

Example 6. Isolating Protein from Potato Juice Using Silicate Polymers

60 ml of potato juice produced according to materials and methods (testsolution 1, protein concentration 13 g/L) is divided into 5 samples (Athrough E respectively) of 12 ml juice and each mixed with 0.25 ml of aconcentrated sodium silicate solution, reagent grade water glass (SigmaAldrich, USA cat. No.: 338443, Na2O=10.6%, SiO2=26.5%) density 1.39 g/mlat 25° C. Addition of the waterglass is performed in aliquots of 0.05 mland pH is immediately adjusted to pH 7 with 1 M hydrochloric acid inbetween each addition. When the full amount of waterglass has been addedthe samples are adjusted to a final pH value of 6.0. Followingincubation for 5 minutes with stirring at ambient temperature thesamples are centrifuged for 5 min at 1430 G and the supernatant (testsolution 2) is separated from the precipitate.

The precipitate remaining in each centrifuge tube is resuspended in 6 mlwater and then centrifuged again. This procedure is repeated twice.Following the last centrifugation, the water washing supernatants arediscarded while the precipitates are transferred into small beakersunder addition of 12 ml water each. The beakers are labelled A-E andadjusted to varying pH values with 1 M sodium hydroxide under stirringas follows: A) pH 7.0, B) pH 8.0, C) pH 9.0, D) pH 10.0 and E) pH 11.0.The samples are then incubated with stirring for 10 min at ambienttemperature where after they are centrifuged for 5 min at 1430 g. Byvisual inspection sample A) through D) contained the same amount ofprecipitate as the first centrifugation at pH 6.0. There was practicallyno remaining precipitate in sample E) pH 11.0. The supernatants A), B),C), D) and E) are separated from the precipitates to form test solution3-7 respectively. The precipitate in each test tube is added 6 ml 0.1 Msodium hydroxide to dissolve the precipitate resulting in test solution8-11. SDS-PAGE is performed on test solutions 1 to 11 as illustrated inFIG. 4 .

The SDS PAGE analysis of FIG. 4 , illustrates that the sodiummetasilicate solution is capable of precipitating almost all the proteinpresent in the potato fruit juice—see lane 2 which shows that only aminor fraction of the PI is left in the supernatant. Further, it is seenthat after washing of the precipitate with water and then incubating atpH 7 results in a highly selective release of PA proteins (see lane 3)with a rather small amount of PI being released from the precipitate.Increasing the pH of the incubation to pH 9.0 (see lane 7 compared tolane 8) results in an almost complete elution of PA and only a fractionof PI resulting in a highly enriched PA supernatant and a PI enrichedprecipitate (see lane 8). At pH 10.0 practically all the precipitatedproteins are released in one pool while it is important to note thatalso at this pH the silicate is still precipitated. Lane 11 illustratesthat practically all the bound proteins are present in the dissolvedprecipitate. There is practically no precipitate left at pH 11 and theproteins are therefore in this sample still in the same fraction as thesilicate.

Example 7. Isolating a Protein Fraction Enriched in PA from Potato Juice

474 ml potato juice produced according to materials and methods (testsolution 1, true protein concentration: 11 g/L) is mixed with 26 mL ofsodium alginate solution (ligand solution A) and pH is adjusted to 3.8using 1 M HCl under thorough stirring. Protein and sodium alginate areallowed to form complexes during mixing for 10 minutes at ambienttemperature.

The solution is then centrifuged for 5 min at 1430 G and the supernatant(test solution 2) separated from the precipitate. The precipitate iswashed briefly by resuspension in water and repeated centrifugation(test solution 3).

The precipitate is then again suspended in water and pH is adjusted topH 7.5 with 1 M NaOH to a final volume of 500 mL (test solution 4).During this step the precipitate is dissolved to produce a slightly hazysolution.

The solubilized precipitate is ultrafiltered using a 100 kDa hollowfiber membrane. When 310 ml permeate (test solution 5) is collected theretentate is diafiltered with four portions of 100 mL 1 mM NaClsolution—the next portion only added after permeation of the foregoingportion. The permeate of each portion of diafiltration is denoted testsolutions 6, 7, 8 and 9, while the retentate resulting from thediafiltration is denoted test solution 10.

SDS-PAGE is performed on the fractions.

SDS-PAGE is performed on test solutions 1 to 4 as depicted in FIG. 5wherein lanes starting from the left are test solutions 1, 2, 3 and 4respectively.

Results:

From the SDS-PAGE of FIG. 5 it is observed that the majority of the PAis precipitated with the polymeric ligand (see lane 2, the PA band intest solution 2 is faint), the majority of the PI's are still in testsolution 2 (see lane 2, the bands representing PI are very strong intest solution 2). Test solution 4 contains a high concentration of PAand a low concentration of PI compared to test solution 1 showing thatPA is isolated in test solution 4 (see lane 4)

SDS-PAGE is performed on test solutions 4 and 5 to 10 as depicted inFIG. 6 , wherein lanes starting from the left are test solutions 4 and 5to 10 respectively.

From the SDS-PAGE gel of FIG. 6 , it is observed that ultra-filteringtest solution 4 enriches PA in the retentate even further. It iscontemplated that during the ultrafiltration and diafiltration of testsolution 4, PI passes the membrane and the PA and LipO is left in theretentate (no PA or LipO is detected in test solutions 5 to 9). Testsolution 10 on the other hand contains a high concentration of PA and alow concentration of PI.

This experiment shows that PA and a fraction of the PI is precipitatedwith sodium alginate at pH 3.8. The precipitate can be collected andredissolved and the PA can be further enriched by ultrafiltrationseparating the majority of PI in the permeate from the ultrafiltrationfilter, while the retentate is a highly enriched PA product mixed withsodium alginate.

Determination of the glycoalkaloid content, color and alkaline coloredphenols of the final PA enriched product (test solution 10) shows thatonly very little of these contaminants are present.

Example 8. Isolating a PA and a PI Fraction from a Precipitate bySelective Elution

21 ml of potato juice produced according to materials and methods (testsolution 1, true protein concentration 7 g/L) is divided into 3 samples(A, B and C respectively) of 7 ml juice and each is mixed with 1 ml of1.5% sodium alginate solution (ligand solution A) and pH is adjusted to3.5 with 1 M hydrochloric acid under thorough stirring at ambienttemperature. The resulting solutions are incubated under stirring for 10min.

The solutions are centrifuged in 3 separate tubes for 5 min at 1430 gand the supernatants removed (test solutions 2-4 respectively). Theprecipitates are briefly washed by resuspension in 5 ml water each andrepeated centrifugation.

The three identical precipitates labelled A, B and C and then washed byresuspension with 7 ml of each of the following solutions:

A: 0.2 M NaCl, 5 mM sodium acetate pH 3.5,

B: 0.4 M NaCl, 5 mM sodium acetate pH 3.5,

C: 0.6 M NaCl, 5 mM sodium acetate pH 3.5.

After mixing the precipitates thoroughly with the salt containingbuffers at ambient temperature the samples are centrifuged 5 min at 1430g. The supernatants, A, B and C are collected for analysis (testsolution 5-7 respectively).

The 3 precipitates are then each added 7 ml 0.1 M potassium phosphate pH7.5 under mixing which dissolves the precipitates to produce slightlyhazy solutions (test solutions 8-10 respectively). SDS-PAGE is performedon test solutions 1-10 as illustrated in FIG. 7 .

Results:

The SDS-PAGE of FIG. 7 illustrates that substantially all the proteinprecipitates at pH 3.5 together with the alginate, only very faintprotein bands are detected in the supernatant, see lane 2, 5 and 8. Itis also concluded that washing the precipitate with salt solution pH 3.5releases mainly PI from the precipitate the higher salt concentrationthe more PI is released, see lane 3, 6 and 9. When washing with 0.6 Msodium chloride pH 3.5 the major part of the PI is released and a minorfraction of PA, see lane 9. After washing the precipitate with 0.6 MNaCl pH 3.5 the resulting solubilized precipitate mainly contains PA anda slight amount of PI, see lane 10.

Example 9. Isolating a PA and a PI Fraction from a Precipitate bySelective Elution

7 ml of potato juice produced according to materials and methods (trueprotein concentration: 7 g/L, test solution 1) is mixed with 1 ml of1.5% sodium alginate solution (ligand solution A) and pH is adjusted to3.5 with 1 M hydrochloric acid under thorough stirring at ambienttemperature. The resulting solution is incubated under stirring for 10min.

The solution is centrifuged for 5 min at 1430 g and the supernatant(test solution 2). The precipitate is briefly washed by resuspension in5 ml water and repeated centrifugation.

The precipitate is then washed by resuspension with 7 ml 0.7 M NaCl, 5mM sodium acetate pH 3.0. After mixing the precipitate thoroughly withthe salt containing acetate buffer for 5 min at ambient temperature thesample is centrifuged 5 min at 1430 g. The supernatant is collected foranalysis (test solution 3). The precipitate is mixed with 7 ml 0.1 Mpotassium phosphate pH 7.5 which dissolves the precipitate to produce aslightly hazy solution (test solution 4). SDS-PAGE is performed on thetest solutions as illustrated in FIG. 8

Results:

The SDS-PAGE of FIG. 8 illustrates that substantially all the proteinprecipitates at pH 3.5 together with the alginate, only very faintprotein bands are detected in the supernatant, see lane 2. It is alsoillustrated that washing the precipitate with 0.7 M NaCl plus acetate pH3.0 releases the major part of PI from the precipitate, see lane 3. Nosignificant amount of PA is released (eluted) during this wash. Afterwashing the precipitate with 0.7 M NaCl pH 3.0 the resulting solubilizedprecipitate mainly contains PA and a small amount of PI, see lane 4.Washing the precipitate with salt solutions at higher pH-values than 3.5elutes both PA and PI to a significant degree.

Determination of the true protein concentration of test solution 3 and 4relative to the starting material (test solution 1) indicates a totalyield corresponding to more than 90%, while practically no true proteinremains in the supernatant (test solution 2).

Determination of the glycoalkaloid content, color and alkaline coloredphenols of the PI enriched product (test solution 3) and the PA enrichedproduct (test solution 4) shows that only very little of thesecontaminants are present, while most of these contaminants remain in thesupernatant (test solution) and water washing fraction.

Example 10. Isolating a PA and PI Fraction from Potato Juice with SodiumAlginate

8 ml potato juice produced according to materials and methods (trueprotein concentration 8 g/L, test solution 1) is mixed with 2 ml of 1.5%sodium alginate solution (ligand solution A) and pH is adjusted in stepsto pH 4.5, pH 4.0, pH 3.5 and pH 3.0 with 1 M hydrochloric acid. At eachpH-value a 250 μl sample is taken out and centrifuged at 2680 g for 5min. The supernatants are collected to produce test solutions 2, 3, 4and 5 respectively.

In a further experiment 13 ml of the same potato juice is mixed with 2ml of ligand solution A and pH is again adjusted to respectively pH 4.5,pH 4.0, pH 3.5 and pH 3.0 with 1 M hydrochloric acid. At each pH-value a250 μl sample is taken out. The samples are centrifuged at 2680 g for 5min. The supernatants are collected to produce test solutions 6, 7, 8and 9, 10 respectively. The test solutions are analyzed with SDS-PAGE asillustrated in FIG. 9 .

Results:

The SDS-PAGE of FIG. 9 illustrates that for both experiments practicallyall the PA is precipitated at pH 4.0, see lane 3 and 6 which has onlyfaint PA bands for both ratios. In addition is it seen that for bothexperiments practically all the proteins are precipitated at pH 3.5, seelane 4 and 7. At lower pH (pH 3.0) a fraction of PI for both ratios isstill in solution, see lane 9 and 10 which indicates that the optimalconditions for a high yield are above pH 3.0.

Example 11. Isolating a PA Enriched Fraction from Potato Juice withSodium Alginate

Second precipitation of non-precipitated proteins with additionalalginate 40 ml of potato juice produced according to materials andmethods (test solution 1, true protein concentration 11 g/L) is mixedwith 1 ml of 1.5% sodium alginate solution (ligand solution A) and pH isadjusted to pH 3.8 with 1 M hydrochloric acid. Following mixing for 5minutes at ambient temperature the sample is centrifuged at 1430 g for10 min. The supernatant is collected (test solution 2). The precipitateis washed by resuspension in water and repeated centrifugation. Theprecipitate is then suspended 35 ml water and pH is slowly adjusted topH 7.5 with 1 M NaOH during mixing at ambient temperature for 30 min.Hereafter the volume of the dissolved precipitated is adjusted to 40 mlby addition of water to produce a slightly hazy solution (test solution3).

The supernatant (40 ml, test solution 2) is adjusted to pH 4.5 and mixedwith 4.4 ml 1.5% sodium alginate solution (produced according tomaterials and methods, ligand solution A) and pH is adjusted to 3.8 with1 M hydrochloric acid during mixing at ambient temperature for 5 min.The sample is then centrifuged at 1430 g for 10 min. The supernatant iscollected (test solution 4). The test solutions are analyzed withSDS-PAGE as illustrated in FIG. 10 .

Results:

The SDS-PAGE of FIG. 10 illustrates that the supernatant from the firstprecipitation (see lane 2) contains only a small fraction of the PAcompared to the starting material). The major part of PI is still insolution (see lane 2, strong PI bands in supernatant).

The dissolved precipitate contains a large amount of PA and only a minorfraction of PI resulting in a highly enriched PA product, see lane 3.

The second precipitation precipitates practically all the remainingprotein, rather weak PI bands are left no detection of PA (see lane 4),resulting in an isolated product mainly containing PI and a minorfraction of the PA (not shown).

Example 12. Isolating Protein from Potato Juice with Polyacrylic AcidPolymer (MW 450,000)

10 ml potato juice produced according to materials and methods (testsolution 1, true protein concentration 9 g/L) is mixed with 1 ml 1.5%polyacrylic acid solution, molecular weight 450,000 (ligand solution E)and pH is adjusted in steps to pH 4.5, pH 4.0 and pH 3.5 respectivelywith 1 M hydrochloric acid. At each pH-value a 250 μl sample is takenout and centrifuged at 2680 g for 5 min. The supernatants (testsolutions 2, 3 and 4 respectively) are collected and analyzed withSDS-PAGE as illustrated in FIG. 11 .

Results:

The SDS PAGE of FIG. 11 illustrates that all the proteins areprecipitated quantitatively at pH 4.5, no protein bands are detected onthe gel, see lane 2. The major part of all the proteins are alsoprecipitated at pH 4.0, only very faint PI bands are detected, see lane3. At pH 3.5 a minor fraction of PI is still in solution while a verysmall amount of PA is detected, see lane 4. The results thus indicatethat the optimal binding conditions are above pH 3.5

Example 13. Isolating Protein from Potato Juice with Polyacrylic AcidPolymer (MW 450,000 and MW 15,000)

Two samples of 20 ml from a potato juice produced according to materialsand methods (test solution 1, true protein concentration: 8 g/L) ismixed with 1 ml 1.5% polyacrylic acid solution, molecular weight 450,000respectively 1.5% polyacrylic acid solution (ligand solution E),molecular weight 15,000 (ligand solution F) and pH is adjusted undermixing to respectively pH 5.0, pH 4.5 and pH 4.0 with 1 M hydrochloricacid. At each pH-value a 250 μl sample is taken out. The samples arecentrifuged at 2680 g for 5 min. The supernatants are collected toproduce test solutions 2-7 respectively and analyzed by SDS-PAGE asillustrated in FIG. 12 .

Results:

The SDS-PAGE of FIG. 12 illustrates that the acrylic acid polymer withhigh molecular weight (450,000 D) precipitates practically all the PAand PI at pH 4.0, see lane 4 (rather weak bands are detected for bothPI, PA and LipO). The polyacrylic acid with a molecular weight of 15,000D also precipitates PA and PI but not as effective as the high molecularweight polymer. The lower pH the more protein is precipitated but stillat pH 4.0 a significant amount of both PA and PI remain in solution, seelane 7.

Example 14. Isolating Protein from Potato Juice with Carrageenan (Kappa,Iota and Lambda)

Three 10 ml samples of a potato juice produced according to materialsand methods (test solution 1, true protein concentration 10 g/L) ismixed with 1 ml of 1.5% kappa carrageenan, iota carrageenan and lambdacarrageenan respectively (ligand solution B, C and D respectively) andpH is adjusted with mixing at ambient temperature for 5 min torespectively 4.5, 4.0 and 3.5 with 1 M hydrochloric acid. At eachpH-value a 250 μl sample is withdrawn. The samples are centrifuged at2680 g for 5 min. The supernatants (test solutions 2-10 respectively)are collected and analyzed by SDS-PAGE as illustrated in FIG. 13 .

Results:

The SDS-PAGE of FIG. 13 illustrates that for all three types ofcarrageenan the lower pH the more protein is precipitated of both PA andPI. Lambda carrageenan is the most effective polymer to precipitate bothPA and PI, already at pH 4.5 most of both PA and PI is precipitated, seelane 8. For Lambda carrageenan at pH 4.0 and 3.5 all the PA isprecipitated, see lane 9 and 10. At pH 4.0 the major part of PI is alsoprecipitated, see lane 9 (very weak PI bands left). There is slightlymore PI in the supernatant at pH 3.5, see lane 10.

For kappa carrageenan, practically all PA is precipitated at pH 3.5, seelane 4 but there is still a fraction of PI in the supernatant. For iotacarrageenan, most of the protein both PA and PI is still in thesupernatant at pH 4.5 and 4.0, see lane 5 and 6. At pH 3.5 a largefraction of the PA is precipitated but a significant fraction of the PIis still in solution.

Example 15. Isolating a PA Fraction from Potato Juice with pH-AdjustmentFollowed by Precipitation of PI Enriched Product with Lambda Carrageenan

50 ml of potato juice produced according to materials and methods (testsolution 1, true protein concentration 11 g/L) is adjusted to pH 3.5with 1 M hydrochloric acid at ambient temperature. The solution is thencentrifuged for 10 min at 1340 g. The supernatant is collected andpH-adjusted to 4.5 (test solution 2). The precipitate is washed byresuspension in 10 ml water and repeated centrifugation. The washingwater is collected after centrifugation (test solution 3). The washedprecipitate is hereafter suspended in 25 ml 0.1 M NaCl. The pH is slowlyadjusted to 7.5 with 1 M NaOH under mixing at ambient temperature todissolve the precipitate and create a hazy solution (test solution 4).The supernatant (test solution 2) is added 2.5 ml 1.5% lambdacarrageenan (ligand solution D) produced according to materials andmethods and pH is adjusted to pH 4.0 with 1 M hydrochloric acid. Thesample is centrifuged at 1340 g for 10 min and the supernatant iscollected (test solution 5). The precipitate is washed by resuspensionin water and repeated centrifugation. Hereafter the precipitate is added25 ml water and pH is slowly adjusted to pH 8.5 under mixing at ambienttemperature to solubilize the precipitate and create a slightly hazysolution (test solution 6).

The test solutions are analyzed by SDS-PAGE as illustrated in FIG. 14and dry matter content is determined according to materials and methodsfor test solution 4 and 6.

Results:

The SDS-PAGE of FIG. 14 illustrates that the pH-adjustment to 3.5 onlyprecipitates PA resulting in a very pure PA product, see lane 4(practically no PI in this fraction). The supernatant contains all thePI and a small amount of PA. The lambda carrageenan precipitatespractically all the protein left in the supernatant, see lane 5 (onlyvery faint bands from PI is left in this fraction). The dissolvedprecipitate contains practically all the PI and a small amount of PA.

Results from dry matter determination: The PA product (test solution 4)contains 187.5 mg dry matter, this corresponds to 3.75 mg dry matter perml juice applied in the test. The enriched PI product (test solution 6)contains 339.9 mg dry matter, which corresponds to is 6.8 mg dry matterper ml juice applied in the test. The dry matter values are correctedfor the content of sodium chloride respectively lambda carrageenan.Therefore, it can be concluded that in a total 10.6 g dry matter isisolated per liter of potato juice applied in the test. Determination ofthe true protein show that the dry matter comprises more than 91%protein when corrected for the content of sodium chloride andcarrageenan corresponding to a yield of 9.65 g true protein. Thus,compared to the starting material (test solution 1) the yield is9.65/11×100%=87.7%

Example 16. Precipitation of Protein from Potato Juice with LambdaCarrageenan, Washing the Precipitate with a Salt Buffer to SelectivelyElute PI and Obtain a PA Enriched Dissolved Product

Three samples of each 10 ml from a potato juice produced according tomaterials and methods (true protein concentration 8 g/L, testsolution 1) is mixed with each 0.71 ml of 1.5% lambda carrageenan(ligand solution D) and pH is adjusted to pH 4.0 with 1 M hydrochloricacid with mixing at ambient temperature for 5 min. The samples arecentrifuged at 1340 g for 10 min. The precipitates are washed byresuspension in water and repeated centrifugation. The first precipitateis then added 10 ml of water and pH is increased to pH 8.0 by slowaddition of 1 M sodium hydroxide resulting in a first re-solubilizedsample (test solution 2). To the second precipitate is added 10 ml 0.3 Msodium chloride, 5 mM sodium acetate pH 4.5 and to the third precipitateis added 10 ml 0.6 M sodium chloride, 5 mM sodium acetate pH 4.5 withmixing. The two still precipitated samples are mixed well for 5 min atambient temperature and centrifuged at 1340 g for 10 min. Thesupernatants are collected as test solution 3 and 4 respectively. 10 mlof water is added to each of the two corresponding precipitates and pHis increased to pH 8.0 by slow addition of 1 M sodium hydroxideresulting in two re-solubilized samples (test solution 5 and 6respectively).

The test solutions are analyzed by SDS-PAGE as illustrated in FIG. 15 .

Results:

The SDS-PAGE of FIG. 15 illustrates that without washing with salt thesolubilized product contains both PA and PI, see lane 2. When washingwith 0.3 M sodium chloride a small amount of PI is released, see lane 3so that the resulting solubilized product still contains a large amountof PI, see lane 4. When increasing the salt concentration to 0.6 Msodium chloride a large amount of especially the PI is released, seelane 5 resulting in a PA enriched fraction, see lane 6.

Example 17 Isolating Protein from Potato Juice Using Silicate Polymers

50 ml of potato juice produced according to materials and methods (testsolution 1, true protein concentration 13 g/L) is divided into 5 samples(A through E respectively) of 10 ml juice and each mixed with 0.25 ml ofa concentrated solution of sodium metasilicate, technical gradewaterglass (Matas, Denmark) 36-38 degrees Baumé, dry matterconcentration 52 wt %. Addition of the waterglass is performed inaliquots of 0.05 ml and pH is immediately adjusted to pH 7 with 1 Mhydrochloric acid in between each addition. When the full amount ofwaterglass has been added the samples are adjusted to the followingfinal pH values: A) 6.1, B) 5.5, C) 4.9, D) 4.5 and E) 3.9. Followingincubation for 5 minutes with stirring at ambient temperature thesamples are centrifuged for 5 min at 1430 G and the supernatant (testsolutions 2-6) separated from the precipitate. SDS-PAGE is performed ontest solutions 1 to 6 as illustrated in FIG. 16 .

Results:

From the SDS-PAGE of FIG. 16 it is observed that almost all the proteinin the juice is precipitated with the water glass at pH 6.1 (lane 2,only a small fraction of the PI is remaining in the supernatant). It isfurther indicated that with decreasing pH the selectivity of theprecipitation becomes pronounced such that at pH 3.9 and 4.5 (lane 5 and6) most of the PI is in solution while almost all the patatin and LipOis precipitated. Remarkably it is further observed by visual inspectionthat all the test solutions 2 through 6 are practically colorlessindicating that the brownish colored polyphenols present in the startingjuice (test solution 1) are eliminated from the protein in solution.

Example 18 Isolating Protein from Potato Juice Using Silicate Polymers

50 ml of potato juice produced according to materials and methods (testsolution 1, true protein concentration 13 g/L) is mixed with 0.5 ml of aconcentrated solution of sodium metasilicate, technical grade waterglass(Matas, Denmark) 36-38 degrees Baumé, dry matter concentration 52 wt %.Addition of the waterglass is performed in aliquots of 0.25 ml and pH isimmediately adjusted to pH 7 with 1 M hydrochloric acid in between eachaddition. When the full amount of waterglass has been added the sampleis adjusted to a final pH of 6.1. Following incubation for 5 minuteswith stirring at ambient temperature the sample is centrifuged for 5 minat 1430 G and the supernatant (test solutions 2) is separated from theprecipitate. SDS-PAGE is performed on test solutions 1 and 2 asillustrated in FIG. 17 .

Results:

The result of the SDS-PAGE of FIG. 17 illustrates that under theseconditions the precipitation is highly selective. LipO is practicallyeliminated from the supernatant while the PA and PI mainly stay insolution. Visual inspection of the supernatant show that also thecolored polyphenols have been removed.

Example 19 Isolating Protein from Potato Juice Using Silicate Polymers

30 ml of potato juice produced according to materials and methods (testsolution 1) is mixed with 1 ml of a concentrated solution of sodiummetasilicate, technical grade waterglass (Matas, Denmark) 36-38 degreesBaumé, dry matter concentration 52 wt %. Addition of the waterglass isperformed in aliquots of 0.25 ml and pH is immediately adjusted to pH 7with 1 M hydrochloric acid in between each addition. When the fullamount of waterglass has been added the sample is adjusted to a final pHof 6.1. Following incubation for 5 minutes with stirring at ambienttemperature the sample is divided into three 10 ml centrifuge tubes andcentrifuged for 5 min at 1430 g and the supernatant from each tube ispoured back into one container (test solution 2). The precipitateremaining in each centrifuge tube is resuspended in 6 ml water and thencentrifuged again. This procedure is repeated twice. Following the lastcentrifugation the water washing supernatants are discarded while theprecipitates are transferred into small beakers under addition of 6 mlwater each. The beakers are labelled A-C and adjusted to varying pHvalues with 1 M hydrochloric acid under stirring as follows: A) pH 2.8,B) pH 1.9, C) pH 1.4. The samples are then incubated with stirring for10 min at ambient temperature where after they are centrifuged for 5 minat 1430 g. The supernatants A), B) and C) are separated from theremaining precipitate to form test solution 3, 4 and 5 respectively.SDS-PAGE is performed on test solutions 1-5 and as illustrated in FIG.18 .

Results:

The SDS PAGE analysis of FIG. 19 illustrates that the sodiummetasilicate is able to precipitate almost all the protein present inthe potato fruit juice (lane 2 which shows that only a minor fraction ofthe PI is left in the supernatant). Further, it can be seen, that afterwashing of the precipitate with water and then incubating at pH 2.8results in a highly selective release of PI proteins (lane 3) withoutany PA being released from the precipitate. Lowering the pH of theincubation to pH 1.9 or pH 1.4 (lane 4 and 5) results in an almostcomplete elution of PA and PI while the LipO remains in the remainingprecipitate.

For all the elutions (test solution 3-5) it is observed that thereleased proteins are practically colorless while the correspondingprecipitates are yellow-brown indicating that the colored polyphenols toa very large extent are separated from the released proteins.

Example 20 Isolating Protein from Potato Juice Using Silicate Polymers

30 ml of potato juice produced according to materials and methods (testsolution 1, true protein concentration 13 g/L) is divided into 2 samples(A and B respectively) of 15 ml juice and each mixed with 0.3 mlrespectively 0.6 ml of a concentrated sodium silicate solution, reagentgrade water glass (Sigma Aldrich, USA cat. No.: 338443, Na2O=10.6%,SiO2=26.5%) density 1.39 g/ml at 25° C. Addition of the water glass isperformed in aliquots of 0.15 ml and pH is immediately adjusted to pH 7with 1 M hydrochloric acid in between each addition. When the fullamount of water glass has been added the samples are adjusted to a finalpH value of 6.0. Following incubation for 5 minutes with stirring atambient temperature the samples are centrifuged for 5 min at 1430 G. Thesupernatants A) and B) are separated from the remaining precipitate toform test solution 2 and 3 respectively. SDS-PAGE is performed on testsolutions 1, 2 and 3 as illustrated in FIG. 19 .

Results:

The SDS PAGE analysis of FIG. 19 illustrates that the sodium silicatesolution from Sigma Aldrich is capable of precipitating almost all theprotein present in the potato fruit juice at pH 6.0. The more waterglass added to the juice the more protein is precipitated. Lane 2 showsthat only a minor fraction of the PI is left in the supernatant A (0.3ml water glass). Lane 3 shows even fainter bands for the PI left in thesupernatant B (0.6 ml water glass.

Example 21 Isolating Protein from Potato Juice Using Sodium and CalciumSilicate (Addition of Solids to the Juice)

100 ml of potato juice produced according to materials and methods (testsolution 1, true protein concentration 13 g/L) is mixed with 700 mgsodium metasilicate powder respectively 350 mg sodium metasilicatepowder (Sigma Aldrich, USA cat. No.: 307815). While the mixing with thesodium metasilicate creates an increase in this is continuously adjustedand stabilized at pH 6.1 with 1 M hydrochloric acid over a period of 10min. Following incubation for 15 minutes with stirring at ambienttemperature the samples are centrifuged for 5 min at 1430 G. Thesupernatants A) and B) (respectively 700 and 350 mg sodium metasilicate)are separated from the remaining precipitate to form test solution 2 and3 respectively.

10 ml of the same batch of potato juice (test solution 1) is mixed with100 mg calcium silicate (Sigma Aldrich, USA cat. No.: 742503) and pH isadjusted to pH 6.0 with 1 M hydrochloric acid. Following incubation for15 minutes with stirring at ambient temperature the sample iscentrifuged for 5 min at 1430 G. The supernatant C) is separated fromthe remaining precipitate to form test solution 4. SDS-PAGE is performedon test solutions 1, 2, 3 and 4 as illustrated in FIG. 20 .

Results:

The SDS PAGE analysis of FIG. 20 illustrates that in contrast to theaddition of soluble sodium silicate (water glass, see e.g. previousexamples) the solid sodium silicate when adding 700 mg per 100 ml juiceonly precipitates rather selectively the LipO while the PI stay insolution together with most of the PA (see lane 1, very weak LipO bandin the supernatant A). When adding 350 mg sodium silicate per 100 mljuice the major content of potato proteins stay in solution (see lane2). Addition of calcium silicate does not precipitate any significantamount of proteins (see lane 4).

Example 22. Synthesis of Polysiloxanes with Organic Functional Groups

Five solutions comprising different organic functional groups andlabelled A) through E) are prepared by mixing at ambient temperature asfollows:

Solution A:

20 ml water is added 2 g 4-aminobenzoic acid (Sigma Aldrich, USA,cat.no.: A9878) followed by adjustment of pH to 11.8 with 5 M sodiumhydroxide.

Solution B:

20 ml water is added 2 g 4-mercaptobenzoic acid (Sigma Aldrich, USA,cat.no.: 706329) followed by adjustment of pH to 11.0 with 5 M sodiumhydroxide.

Solution C:

20 ml water is added 2 g hexylamine (Sigma Aldrich, USA, cat.no.:219703).

Solution D:

20 ml water is added 2 g benzylamine (Sigma Aldrich, USA, cat.no.:A9878).

Solution E:

20 ml water is added 2 g benzylaminoethanol (Sigma Aldrich, USA,cat.no.: B22003).

To each solution is then added 5 ml glycidoxypropyltrimethoxysilane(Sigma Aldrich, USA, cat.no.: 440167) under constant stirring and thetemperature is increased to 40 degrees Celsius. The reaction is carriedout for 18 hours after which the solutions are cooled to ambienttemperature and each applied for dialysis against 5 L demineralizedwater in dialysis tubing cellulose membranes (Sigma-Aldrich, USA, cat.No.: D9652). The dialysis is continued for 48 hours at ambienttemperature with 4 shifts of the water. Following removal of any surplusand unreacted reactants by dialysis acid-base titrations and elementalanalysis for determination of nitrogen, sulfur and silicon confirm thatthe glycidoxypropyltrimethoxysilane reacts with the added organicfunctional groups. All solutions also form a heavy precipitate uponacidification with hydrochloric acid.

Example 23. Isolation of Potato Proteins Using Polysiloxanes Coupledwith Organic Functional Groups

50 ml of potato juice produced according to materials and methods (testsolution 1, protein concentration 10 g/L) is mixed with a solution ofthe polysiloxane—4-mercatobenzoic acid derivative prepared according toexample 22 to reach a final concentration of 10 mg polysiloxanederivative per ml potato juice and pH is adjusted to pH 5.1 at ambienttemperature. A heavy precipitate is formed. Following mixing for 5minutes the mixture is centrifuged at 1430 g for 10 minutes. Theresulting supernatant is decanted (test solution 2) and analyzed bySDS-PAGE according to materials and methods. From the SDS-PAGE analysisit is concluded that most of the PI in the sample is bound while only asmaller fraction of the PA is removed.

Example 24. Pre-Treatment of Potato Juice with Calcium Chloride andWater Glass

200 ml of potato juice produced according to materials and methods (testsolution 1, true protein concentration 11 g/L) is divided into 2 samples(A and B respectively) of 100 ml juice. Calcium chloride (1 M solution)and water glass solution (from Borup Kemi, Denmark, 36° BE) are added inthe following concentrations:

A: 0 ml 1 M CaCl2)+0 ml water glass=reference

B: 1 ml 1 M CaCl2) (10 mM)+0.5 ml water glass

The solutions are incubated for 1 hr at room temperature. The solutionsare then centrifuged in 2 separate tubes for 10 min at 1430 g and thesupernatants are collected (test solutions 2 and 3 respectively). Theturbidity of the supernatants is measured by spectrophotometry at 620nm.

The test solutions are then freeze dried and the amount ofglycoalkaloids (solanine and chaconine) are determined in the two driedproducts. Protein composition is determined by SDS-PAGE.

Results:

Table 3 below shows the 620 nm reading and glycoalkaloid content of thedry substances derived from test solution 2 and 3.

Test solution 620 nm reading Solanine, ppm Chaconine, ppm 2 (reference)0.721 1336 107 3 0.313 1026 0

It is concluded that a pre-treatment of the juice with calcium chlorideand water glass, reduces the turbidity significantly compared to theuntreated reference. The content of chaconine in the pretreated solutionis eliminated completely while the solanine content is reduced with 23%.

Analysis by SDS-PAGE revealed no significant change in the compositionand concentration of the major protein groups in the pretreated samplecompared to the reference.

Example 25. Pre-Treatment of Potato Juice with Different CalciumChloride and Water Glass Concentrations

2400 ml of potato juice produced according to materials and methods(test solution 1, true protein concentration 11 g/L) is divided into 4samples (A, B, C and D respectively) of 600 ml juice. Calcium chloride(1 M solution) and water glass solution (from Borup Kemi, Denmark, 36°BE) are added in the following concentrations:

A: 6 ml 1 M CaCl2) (10 mM)+3 ml water glass (5 ml/L)

B: 6 ml water (0 mM)+3 ml water glass (5 ml/L)

C: 12 ml 1 M CaCl2) (20 mM)+3 ml water glass (5 ml/L)

D: 12 ml 1 M CaCl2 (20 mM)+4.5 ml water glass (7.5 ml/L)

The solutions are incubated for 1 hr at room temperature. The solutionsare then centrifuged in 4 separate tubes for 10 min at 1430 g and thesupernatants are collected (test solutions 2-5 respectively). Theturbidity of the supernatants and non-treated juice is measured byspectrophotometry at 620 nm.

Results:

Table 4 shows the 620 nm reading for test solutions 1-5.

Test solution CaCl2, mM Water glass ml/L 620 nm reading 1 0 0.0 0.721 210 5.0 0.313 3 0 5.0 0.366 4 20 5.0 0.243 5 20 7.5 0.186

The experiment shows that by adding only water glass at 5 ml/L juice the620 nm signal is reduced from 0.721 to 0.366 relative to the untreatedjuice (test solution 1). By also adding 10 mM calcium chloride to thejuice containing 5 ml/L water glass (test solution 2) the 620 nm signalis decreased further 15% from 0.366 to 0.313. Increasing theconcentration of calcium chloride further to 20 mM in juice containing 5ml/L water glass (test solution 4) reduces the 620 nm signal withfurther 22% from 0.313 to 0.243. An increase of calcium chloride to 20mM and the water glass from 5 to 7.5 ml/L juice reduces the 620 nmreading with 74% relative to the untreated juice.

The brown coloration of test solution 4 and 5 were significantly lessthan in test 1, 2 and 3 indicating an efficiently removal of phenoliccompounds such as polyphenols as well.

Analysis by SDS-PAGE revealed no significant change in the compositionand concentration of the major protein groups in the pretreated samplecompared to the reference.

Example 26. Pre-Treatment of Potato Juice with Calcium Chloride andWater Glass at Different Temperature and Incubation Time

300 ml of potato juice produced according to materials and methods (testsolution 1, true protein concentration 11 g/L) is divided into 3 samples(A, B and C respectively) of 100 ml juice. Calcium chloride (1 Msolution) and water glass solution (from Borup Kemi, Denmark, 36° BE)are added in the following concentrations to all three samples: 1 ml 1 MCaCl2 (10 mM)+0.5 ml water glass (5 ml/L)

The solutions are then incubated for a total of 1 hr at the followingtemperatures:

A: Room temperature, 22° C.

B: 30° C. in a controlled temperature water bath

C: 37° C. in a controlled temperature water batch

For each temperature, 4 ml samples are withdrawn after 5, 10, 15 and 60min of incubation.

The withdrawn samples are immediately centrifuged in separate tubes for5 min at 1430 g and the supernatants are collected (A: test solution 2,3, 4 and 5 respectively, B: test solution 6, 7, 8 and 9 respectively, C:test solution 10, 11 and 12 respectively). The turbidity of the testsolutions is measured by spectrophotometry at 620 nm.

Results:

Table 5 shows the 620 nm reading for test solution 1-13.

Test solution Temperature, ° C. Incubation time, min 620 nm reading 1 22— 1.043 2 22 5 0.485 3 22 10 0.427 4 22 15 0.377 5 22 60 0.334 6 30 50.358 7 30 10 0.340 8 30 15 0.295 9 30 60 0.252 10 37 5 0.230 11 37 100.222 12 37 15 0.196 13 37 60 0.188

The experiment shows that for all three temperatures the turbiditydecreases over time while higher temperature leads to a faster and moreefficient precipitation of the light scattering substances.

Example 27. Isolating Protein from Pretreated Potato Juice Using SodiumAlginate

700 ml of potato juice produced according to materials and methods (testsolution 1, true protein concentration 10 g/L) pretreated with calciumchloride and water glass and centrifuged as described in example A ismixed with 100 ml of 1.5% sodium alginate solution (ligand solution A)and pH is adjusted to 3.5 with 1 M hydrochloric acid under thoroughstirring at ambient temperature. The resulting solution is incubatedunder stirring for 10 min. The solution is then centrifuged for 10 minat 1430 g and the supernatant removed (test solution 2). The precipitateis washed twice by resuspension in 200 ml water at pH 3.0 (with 1 Mhydrochloric acid) and repeated centrifugation. The resultingprecipitate is then dissolved in 100 ml water by adjustment of pH to pH7.5 with 1 M NaOH. The dissolved product is dried by freeze drying(Product 1).

The concentration of glycoalkaloids (solanine and chaconine) as well asthe protein content (N×6.25) is determined on product 1 afterfreeze-drying.

Results:

A yield of 7.5 gram dried Product 1 was achieved after freeze drying.

Table 6 shows the content of glycoalkaloids and protein in thefreeze-dried product 1.

Sample Protein content, % Solanine, ppm Chaconine, ppm Product 1 74.6 755

Example 28. Isolating a PA Enriched Fraction and a PI Fraction fromPretreated Potato Juice with Sodium Alginate Precipitation Followed byUltrafiltration

2.2 L of potato juice produced according to materials and methods (testsolution 1, true protein concentration 9 g/L) and pretreated withcalcium chloride and water glass and centrifuged as described in exampleA is mixed with 63 ml of 1.5% sodium alginate solution (ligand solutionA) and pH is adjusted to pH 3.5 with 1 M hydrochloric acid.

Following mixing for 5 minutes at ambient temperature the sample iscentrifuged at 1430 g for 10 min. The supernatant is collected (testsolution 2). The precipitate is washed two time by resuspension in waterpH adjusted to 3.0 with hydrochloric acid and repeated centrifugation.The precipitate is then suspended in 100 ml water and pH is slowlyadjusted to pH 10 with 1 M NaOH during mixing at ambient temperature for30 min. (test solution 3).

The supernatant (2.25 L, test solution 2) is ultrafiltered at pH 3.5using a 10 kDa hollow fiber membrane. When 2.05 L permeate (testsolution 4) is collected the retentate is diafiltered with six additionsof 200 mL water pH adjusted with hydrochloric acid to 3.0. The permeateof each addition of diafiltration water is pooled and denoted testsolution 5, while the retentate resulting from the diafiltration isdenoted test solution 6.

The test solutions are analyzed with SDS-PAGE as illustrated in FIG.21-22 .

Test solution 3 and 6 are freeze dried resulting in respectively product1 (PA enriched fraction) and product 2 (PI enriched fraction). Theconcentration of glycoalkaloids (solanine and chaconine) is determinedin dried product 1 and product 2.

Furthermore the protein content (N×6.25) is determined in dried product1 and product 2.

Results:

The SDS-PAGE of FIG. 21-22 illustrates that the supernatant from thealginate precipitation (see lane 2) contains only a very small fractionof the PA compared to the starting material. The major part of PI isstill in solution resulting in a highly enriched PI fraction, product 2(see lane 3, strong PI bands in retentate).

The dissolved precipitate contains PA and only a minor fraction of PIresulting in a highly enriched PA product (product 1), see lane 4.

The ultrafiltered and diafiltered PI enriched product (see lane 3) havevery similar protein profile as the supernatant from the alginateprecipitation (see lane 2) meaning that only a very small amount ofprotein pass through the 10 kDa hollow fiber membrane duringultrafiltration and diafiltration when performed at pH 3.5 (see lane 5and 6, no protein bands are detected in test solution 4 and 5).

The yield of product 1 was 11.2 g

The yield of product 2 was 10.4 g

Table 7 shows the content of glycoalkaloids and protein in the freezedried product 1 and product 2.

Sample Protein content, % Solanine, ppm Chaconine, ppm Product 1 (PA73.2 54 <10 enriched) Product 2 (PI 83.7 270 <10 enriched)

Example 29. Pre-Treatment of Potato Juice with Different CalciumChloride and Water Glass Concentrations at Room Temperature (20-22° C.)

400 ml of potato juice produced according to materials and methods (testsolution 1, true protein concentration 11 g/L) is divided into 4 samples(A, B, C and D respectively) of 100 ml juice. Calcium chloride (1 Msolution) and water glass solution (from Borup Kemi, Denmark, 36° BE)are added in the following concentrations:

A: 1 ml 1 M CaCl2) (10 mM)+0.67 ml water glass (6.7 ml/L)

B: 1 ml water (0 mM)+0.67 ml water glass (6.7 ml/L)

C: 1 ml 1 M CaCl2) (10 mM)+0.5 ml water glass (5.0 ml/L)

D: 1 ml water (0 mM)+0.5 ml water glass (5.0 ml/L) For each solution, 5ml samples are withdrawn after 5, 10, 15 and 30 min of incubation.

The withdrawn samples are immediately centrifuged in separate tubes for5 min at 1430 g and the supernatants are collected (A: test solution 2,3, 4 and 5 respectively, B: test solution 6, 7, 8 and 9 respectively, C:test solution 10, 11, 12 and 13 respectively, D: test solution 14, 15,16 and 17 respectively). The turbidity of the test solutions is measuredby spectrophotometry at 620 nm.

Results:

Table 8 shows the 620 nm reading for test solutions 1-17.

Test Water glass, Incubation time, 620 nm solution CaCl2, mM ml/L minreading 1 0 0 — 1.043 2 10 6.7 5 0.432 3 10 6.7 10 0.298 4 10 6.7 150.277 5 10 6.7 30 0.278 6 0 6.7 5 0.480 7 0 6.7 10 0.357 8 0 6.7 150.331 9 0 6.7 30 0.321 10 10 5.0 5 0.416 11 10 5.0 10 0.425 12 10 5.0 150.390 13 10 5.0 30 0.347 14 0 5.0 5 0.454 15 0 5.0 10 0.452 16 0 5.0 150.416 17 0 5.0 30 0.373

The experiment shows that for all the test solutions the turbiditydecreases over time while a higher water glass concentration leads to amore efficient precipitation of the light scattering substances.Addition of 10 mM Calcium chloride results in a lower turbidity thansolutions without calcium chloride for both concentrations of waterglass.

Example 30. Pre-Treatment of Potato Juice with Different CalciumChloride and Water Glass Concentrations at 35° C.

400 ml of potato juice produced according to materials and methods (testsolution 1, true protein concentration 11 g/L) is divided into 4 samples(A, B, C and D respectively) of 100 ml juice. Calcium chloride (1 Msolution) and water glass solution (from Borup Kemi, Denmark, 36″BE) areadded in the following concentrations:

-   -   A: 0 ml 1 M CaCl2) (0 mM)+0 ml water glass (0 ml/L)    -   B: 1 ml 1 M CaCl2) (10 mM)+0 ml water glass (0 ml/L)    -   C: 1 ml 1 M CaCl2) (10 mM)+0.33 ml water glass (3.33 ml/L)    -   D: 1 ml 1 M CaCl2 (10 mM)+0.25 ml water glass (2.5 ml/L)

For each solution, 5 ml samples are withdrawn after 5, 10, 15 and 30 minof incubation at 35° C. in a controlled temperature water bath.

The withdrawn samples are immediately centrifuged in separate tubes for5 min at 1430 g and the supernatants are collected (A: test solution 2,3, 4 and 5 respectively, B: test solution 6, 7, 8 and 9 respectively, C:test solution 10, 11, 12 and 13 respectively, D: test solution 14, 15,16 and 17 respectively). The turbidity of the test solutions is measuredby spectrophotometry at 620 nm.

Results:

Table 9 shows the 620 nm reading for test solutions 1-17.

Water glass, Incubation time, 620 nm Test solution CaCl2, mM ml/L minreading 1 0 0 — 1.043 2 0 0 5 0.604 3 0 0 10 0.574 4 0 0 15 0.576 5 0 030 0.575 6 10 0 5 0.529 7 10 0 10 0.498 8 10 0 15 0.510 9 10 0 30 0.49610 10 3.33 5 0.346 11 10 3.33 10 0.336 12 10 3.33 15 0.311 13 10 3.33 300.315 14 10 2.5 5 0.416 15 10 2.5 10 0.397 16 10 2.5 15 0.375 17 10 2.530 0.370

The experiment shows that when incubating at 35° C. the effect of thepre-treatment is practically complete within 10 minutes. The addition ofcalcium chloride and water glass decreases the turbidity mostefficiently.

Example 31. Pre-Treatment of Potato Juice with Water Glass at DifferentConcentrations

800 ml of potato juice produced according to materials and methods (testsolution 1, true protein concentration 11 g/L) is divided into 4 samples(A, B, C and D respectively) of 200 ml juice. Water glass solution (fromBorup Kemi, Denmark, 36° BE) are added in the following volumes:

A: 10 ml/L

B: 6.7 ml/L

C: 5 ml/L

D: 5 ml/L+2 ml 1 M CaCl2 (10 mM)=reference solution

The solutions A, B and C are then incubated for 1 hr at room temperature(20-22° C.). Solution D is incubated for 1 hr at 35° C. in a controlledtemperature water bath.

The samples are immediately centrifuged in separate tubes for 10 min at1430 g and the supernatants are collected (A: test solution 2, B: testsolution 3, C: test solution 4, D: test solution5). The turbidity of thetest solutions is measured by spectrophotometry at 620 nm.

Results:

Table 10 shows the 620 nm reading for test solution 1-5.

620 nm Test solution Temperature CaCl2, mM Water glass ml/L reading 1Room temp. 0 0.0 0.721 2 Room temp. 0 10.0 0.223 3 Room temp. 0 6.70.428 4 Room temp. 0 5.0 0.642 5 35° C. 10 5.0 0.271

The experiment shows that the turbidity decreases when the concentrationof water glass increases and a more efficient precipitation of the lightscattering substances is achieved. Elevated temperature (35° C.)decreases the turbidity significantly even at the relatively lowerconcentration of water glass.

Example 32. Isolating a PA Enriched Fraction with pH Adjustment fromPretreated Potato Juice (with Water Glass)

200 ml of potato juice produced according to materials and methods (testsolution 1, true protein concentration 11 g/L) is pre-treated byaddition of 2 ml water glass solution (from Borup Kemi, Denmark, 36° BE)followed by incubation at room temperature (20-22° C.) for 1 hr. Thesample is then centrifuged for 10 min at 1430 g and the supernatant iscollected (test solution 2). The turbidity of test solution 2 ismeasured by spectrophotometry at 620 nm.

Test solution 2 is then adjusted to pH 3.0 with 1 M hydrochloric acid.The sample is then centrifuged again at 1430 g for 10 min. Thesupernatant is collected (test solution 3). The turbidity of testsolution 3 is measured by spectrophotometry at 620 nm.

The precipitate is washed by resuspension in water pH adjusted to 3.0with hydrochloric acid and repeated centrifugation (precipitate 1).

Precipitate 1 is then suspended in 50 ml water and pH is slowly adjustedto pH 9 with 1 M NaOH during mixing at ambient temperature, total volumewas then 55 ml (test solution 4).

The test solutions are analyzed with SDS-PAGE as illustrated in figurexx.

The dry matter content in the PA enriched product (test solution 4) isdetermined

Results:

The SDS-PAGE of FIG. 22 illustrates that the supernatant from the pHprecipitation (see lane 3) contains only a very small fraction of the PAcompared to the starting material. The major part of PI is still insolution resulting in a highly enriched PI fraction (see lane 3, strongPI bands). The dissolved precipitate contains PA and only aninsignificant fraction of PI resulting in a highly enriched PA product,see lane 4.

Table 11 shows the 620 nm reading for test solution 2 and 3

Test solution Sample description 620 nm reading 2 Pre-treated juice0.321 3 Supernatant at pH 3 0.105

The low turbidity of test solution 3 (containing the non-precipitated PIfraction) is highly advantageous for further processing e.g. by membranefiltration or an additional precipitation step.

The dry matter content in test solution 4 was 1.80%, and with a volumeof 55 ml this results in a yield of 4.95 g/L potato juice.

When compared to a corresponding dissolved precipitate containing PAfrom a potato juice that is not pre-treated according to the invention,test solution 4 would have significantly better re-solubilizationcharacteristics and a lower turbidity.

Example 33. Isolating a PI Fraction with pH Adjustment from ImmediatelyProcessed Potato Juice

Part A

1000 ml of potato juice was produced from raw potatoes as described inmaterials and methods except that the potatoes and the juicer werepre-heated to 40 degrees Celsius and the initial removal of largerparticles by centrifugation was not performed (test solution 1, trueprotein concentration 8.5 g/L). Within less than 10 minutes fromproducing the juice and adding the sodium sulfite, test solution 1 wasdivided into four fractions of each 250 ml and adjusted in pH asfollows: The first 250 ml fraction was adjusted to pH 4.0 (test solution2), the second fraction was adjusted to pH 3.5 (test solution 3), thethird fraction was adjusted to pH 3.0 and the fourth fraction wasadjusted to pH 2.5. All pH adjustments were performed using 1 M sulfuricacid.

The four fractions were then centrifuged at 1430 G for 10 minutes andthe four supernatants separated from the precipitates. The foursupernatants were subsequently analysed by SDS-PAGE, scanningdensitometry and spectrophotometry to determine the optical density at620 nm and by an assay to determine the content of polyphenoloxidase asdescribed in materials and methods.

Part B

2000 ml potato juice prepared as in Part A was adjusted to pH 3.0 withinless than 10 minutes from producing the juice and centrifuged at 1430 Gfor 10 minutes. The precipitate from the centrifugation was immediatelyfrozen and stored while the resulting clear supernatant was thenultrafiltered on a 10 kD cut-off hollow fiber cartridge to concentratethe supernatant 10 times and hereafter a diafiltration step using, first5 retentate volumes of water/H2SO4 pH 3.0 and then 5 retentate volumesof demineralized water was performed. The resulting slightly turbidsolution (approx. 200 ml) was subsequently freeze-dried and analysed forprotein purity by Kjeldahl nitrogen determination, solanine content,gelling functionality and solubility.

Part C

This test was carried out in the same way as described for Part B abovewith an additional adsorption step after the last diafiltration stepwith demineralized water as follows: The retentate (approx. 200 ml) wasincubated with mixed at room temperature with 10 ml Dowex optipore L-285resin (adsorbent from DOW Chemical Company) for 6 hours. Followingincubation the suspension was allowed to rest and the resin was allowedto settle. The supernatant above the settled resin was recovered bydecantation, freeze dried and analyzed for solanine and chaconinecontent.

Part D

This test was carried out in the same way as descriped in Part C exceptthat the resin (adsorbent) used was a Lewatite VP OC 1064 adsorbent(from LanXess).

Results:

Part A

Measured concentrations of lipoxygenase, polyphenoloxidase, PA and PIrelative to test solution 1 (100%).

Supernatant/Test Lipoxygenase Polyphenol OD solution % oxidase % PA % PI% 620 nm 2 (pH 4.0) 35 Approx. 25 >85 >95 0.09 3 (pH 3.5) <10 Approx. 1050 >95 0.06 4 (pH 3.0) ND ND <10 >95 0.03 5 (pH 2.5) ND ND ND >95 0.03ND: Not detected From these data it is concluded that the highest purityof the PI relative to PA, lipoxygenase and polyphenoloxidase under theconditions tested is achieved by acididification of the juice to pHabout 2.5-3.0.

Part B.

The yield of the PI dried protein fraction corresponded to 4.8 g/L testsolution 1, corresponding to approx. 95% of the PI present in testsolution 1. The freeze-dried PI powder was off-white to slightly yellow,had a bland to slightly acidic taste and was found to be more than 90%soluble in an aqueous phosphate buffer (0.05 M, pH 7.4). A 2% solutionin 0.05 M sodium acetate pH 4.5 formed excellent and firm gels byheating to 80 degrees C. for 30 min. The protein content of the powderas determined by the Kjeldahl method was 88% and the solanine contentwas 145 ppm.

Thus, it is concluded that the applied separation process from crude andfreshly made potato juice provides a highly functional and non-denaturedPI protein fraction having high purity.

Part C.

The solanine and chaconine content of the freeze dried powder was foundto be 35 and 22 ppm respectively which demonstrates that the Dowexadsorbent bound and removed a substantial amount of the glycoalkaloidpresent in the untreated retentate (see Part B).

Part D.

The solanine and chaconine content of the freeze dried powder was bothfound to be less than 10 ppm which demonstrates that the Dowex adsorbentbound and removed a substantial amount of the glycoalkaloid present inthe untreated retentate (see Part B).

ITEMS OF THE INVENTION

1. A method for isolating a first group of compounds selected from oneor more of patatin protein (PA), protease inhibitor protein (PI),lipoxygenase (LipO) and polyphenol oxidase (PPO) from a second group ofcompounds selected from one or more of PA, PI, LipO, PPO, glycoalkaloidand phenolic compounds said method comprising:

a) providing an aqueous phase comprising compounds selected from two ormore of PA, PI, PPO, LipO, glycoalkaloid and phenolic compounds of whichat least one compound is selected from PA, PI, LipO and PPO;

b) contacting the aqueous phase with a mobile solubilized ligand atphysico-chemical conditions allowing formation of a complex between theligand and the compounds selected from one or more of PA, PI, LipO andPPO;

c) allowing the complex to separate from the aqueous supernatant phase,optionally by changing said physico-chemical conditions in thecomposition to reduce the solubility of the complex; and

d) isolating the complex separated from the aqueous phase.

2. The method of item 1, wherein the separated complex comprises acombination of PA and PI and PPO and wherein the complex separates fromthe aqueous supernatant phase by precipitation.

3. The method of item 2, wherein the dry weight ratio PA:PI in theprecipitate is higher than the dry weight PA:PI ratio for PA and PIremaining dissolved in the aqueous supernatant phase.

4. The method of item 3, further comprising dissolving the precipitatedcomplex in an aqueous solvent and isolating PA from one or morecompounds selected from PI and PPO by a mechanical separation processconcentrating the PA in the retentate

5. The method of item 3, further comprising isolating the precipitatedcomplex by a mechanical separation process concentrating one or more ofPA, PI and PPO in the retentate.

6. The method of item 2, further comprising

a) contacting the aqueous supernatant phase with a further mobilesolubilized ligand at physico-chemical conditions in the aqueoussupernatant phase allowing formation of a complex between the ligand andcompounds selected from one or more of PI, and PPO;

b) allowing the complex to separate from the aqueous supernatant phase,optionally by changing said physico-chemical conditions in thecomposition to reduce the solubility of the complex so that the complexseparates from the aqueous supernatant phase; and

c) isolating the complex.

7. The method of item 2, wherein the sum of PA and PI remainingdissolved in the aqueous supernatant phase is less than 20%, optionallyless than 10 wt. % of the total PA and PI.

8. The method of item 7, further comprising dissolving the precipitatedcomplex in an aqueous solvent and isolating PA from one or morecompounds selected from PI, and PPO by a mechanical separation processconcentrating the PA in the retentate.

9. The method of item 7, further comprising isolating the precipitatedcomplex by mechanical separation process concentrating the one or moreof PA, PI, and PPO in the retentate.

10. The method of item 7, further comprising dissolving the precipitatedcomplex in an aqueous solvent and isolating PA from one or morecompounds selected from PI, and PPO by selectively adsorbing the one ormore compounds selected from PI and PPO on an immobilized solid carrierat conditions where the carrier will bind the one or more compoundsselected from PI and PPO.

11. The method of item 2, wherein the dry weight ratios PI:PA or PPO:PAin the precipitate is higher than the dry weight ratios PI:PA or PPO:PAfor PA, PI and PPO remaining dissolved in the aqueous supernatant phase.

12. The method of item 11, further comprising concentrating PA in theaqueous supernatant phase by a mechanical separation processconcentrating PA in the retentate, optionally combined withdiafiltation.

13. The method of item 11, further comprising

a) contacting the aqueous supernatant phase with a further mobilesolubilized ligand at physico-chemical conditions in aqueous supernatantphase allowing formation of a complex between the ligand and PA;

b) allowing the complex to separate from the aqueous supernatant phase,optionally by changing said physico-chemical conditions in thecomposition to reduce the solubility of the complex so that the complexseparates from the aqueous supernatant phase; and

c) isolating the complex.

14. The method of item 11, further comprising adsorbing dissolved PA inthe aqueous supernatant phase on an immobilized solid carrier atconditions where the carrier will bind PA.

15. The method of item 1, further comprising pre-treating the aqueousphase of 1a) by adsorbing one or more of PI, LipO and PPO on animmobilized solid carrier at conditions where the carrier will bind theone or more of PI, LipO or PPO.

16. The method of any preceding items, wherein the isolated complexcomprises one or more of PA, PI, LipO and PPO.

17. The method of item 16, wherein the isolated complex on a dry weightbasis comprises more than 51.9 wt % PA, optionally more than 55 wt % PA,optionally more than 65 wt % PA, optionally more than 75 wt % PA,optionally more than 85 wt % PA, optionally more than 95 wt % PArelative to the total amount of PA, PI, LipO and PPO in the isolatedcomplex.

The method of item 16, wherein the isolated complex comprises more than88.6 wt % PA of total PA, optionally more than 90 wt % PA of total PA,optionally more than 95 wt % PA of total PA, optionally more than 97 wt% PA of total PA, optionally more than 99 wt % PA of total PA.

18. The method of item 16, wherein the isolated complex on a dry weightbasis comprises more than 50 wt % PI, optionally more than 55 wt % PI,optionally more than 65 wt % PI, optionally more than 75 wt % PI,optionally more than 85 wt % PI, optionally more than 95 wt % PIrelative to the total amount of PA, PI, LipO and PPO in the isolatedcomplex.

19. The method of item 16, wherein the isolated complex comprises morethan 90 wt % PI of total PI, optionally more than 95 wt % PI of totalPI, optionally more than 97 wt % PI of total PI, optionally more than 99wt % PI of total PI.

20. The method of item 16, wherein the isolated complex on a dry weightbasis comprises more than 50 wt % PPO, optionally more than 55 wt % PPO,optionally more than 65 wt % PPO, optionally more than 75 wt % PPO,optionally more than 85 wt % PPO, optionally more than 95 wt % PPOrelative to the total amount of PA, PI, LipO and PPO in the isolatedcomplex.

21. The method of item 16, wherein the isolated complex comprises morethan 90 wt % PPO of total PPO, optionally more than 95 wt % PPO of totalPPO, optionally more than 97 wt % PPO of total PPO, optionally more than99 wt % PPO of total PPO.

22. The method of item 16, wherein the isolated complex relative to thetotal amount of PA, PI, LipO and PPO in the isolated complex comprisesfrom 60 to 95 wt % PA; and from 0.9 to 39.9 wt % PI and from 0.1 to 4.1wt % PPO.

23. The method of item 16, wherein the isolated complex comprises from80-99.9 wt % PA of total PA in the aqueous phase; from 0.1 to 20 wt % PIof total PI in the aqueous phase and from 0.1 to 20 wt % PPO of totalPPO in the aqueous phase.

24. The method of any of items 1 to 23, wherein the PA is complexed tothe ligand in a PA:ligand dry weight ratio of at least 4:1, optionallyat least 8:1, optionally at least 10:1, optionally at least 15:1.

25. The method of any of items 1 to 23, wherein the PI is complexed tothe ligand in a PI:ligand dry weight ratio of at least 3:1, optionallyat least 5:1, optionally at least 8:1, optionally at least 10:1.

26. The method of any of items 1 to 23, wherein the PPO is complexed tothe ligand in a PPO:ligand dry weight ratio of at least 2:1, optionallyat least 4:1 optionally at least 7:1

27. The method of any of items 1 to 23, wherein the PA is complexed tothe ligand in a PA:ligand dry weight ratio of at least 6:1; the PI iscomplexed to the ligand in a PI:ligand dry weight ratio of at least 5:1and the PPO is complexed to the ligand in a PPO:ligand dry weight ratioof at least 2:1, optionally in a PA:ligand dry weight ratio of at least6:1; the PI is complexed to the ligand in a PI:ligand dry weight ratioof at least 7:1 and the PPO is complexed to the ligand in a PPO:liganddry weight ratio of at least 2:1.

28. The method of item 3, wherein the PA:PI dry weight ratio in theprecipitate is at least 25% higher than the PA:PI dry weight ratio forPA and PI remaining dissolved in the aqueous supernatant phase,optionally at least 50% higher, optionally at least 75% higher.

29. The method of item 7, wherein the sum of PA and PI remainingdissolved in the aqueous supernatant phase is less than 15 wt. % of thetotal PA and PI, optionally less than 12%, optionally less than 10%,optionally less than 8%, optionally less than 6%, optionally less than5%, optionally less than 4%, optionally less than 3%, optionally lessthan 2%, optionally less than 1%, optionally less than 0.5%.

30. The method of any of items 1 to 29, wherein the complex containsless than 200 milligrams of glycoalkaloid per kilogram dry matter,optionally less than 150, optionally less than 110, optionally less than95 mg, optionally less than 80, optionally less than 65, optionally lessthan 45, optionally less than 25, optionally less than 10 milligramglycoalkaloid per kilogram dry matter.

31. The method of any of items 1 to 29, wherein at least 50%, optionallyat least 65%, optionally at least 75%, optionally at least 82%,optionally at least 89%, optionally at least 93% of the glycoalkaloid inthe aqueous phase remains in the aqueous supernatant phase afterseparation of the complex.

32. The method of any of items 1 to 29, wherein the complex containsless than 300 milligram phenolic compounds per kilogram dry matter.optionally less than 250, optionally less than 200, optionally less than150, optionally less than 125, optionally less than 95, optionally lessthan 70, optionally less than 35 milligram phenolic compounds perkilogram dry matter.

33. The method of any of items 1 to 29, wherein at least 50%, optionallyat least 65%, optionally at least 75%, optionally at least 85%,optionally at least 90% of the phenolic compounds in the aqueous phaseremains in the aqueous supernatant phase after separation of thecomplex.

34. The method of any preceding items, wherein the phenolic compound ischlorogenic acid.

35. The method of item 34, wherein the complex comprise, on a dry weightbasis, less than 120 mg/kg of chlorogenic acid, optionally less than 100mg/kg, optionally less than 80 mg/kg, optionally less than 60 mg/kg,optionally less than 40 mg/kg, optionally less than 20 mg/kg, optionallyless than 10 mg/kg.

36. The method of any preceding items, wherein the aqueous phase of stepa) comprise an aqueous solution liberated when disintegrating a portionof a plant optionally a tuber portion of a plant of the genus Solanum,optionally of the species S. tuberosum.

37. The method of item 36, wherein the aqueous phase of step a) comprisethe liberated aqueous solution diluted with less than 50 wt % addedsolvent, optionally less than 25 wt % added solvent, optionally lessthan 20 wt % added solvent, optionally less than 15 wt % added solvent,optionally less than 10 wt % added solvent, optionally less than 5 wt %added solvent, optionally less than 2 wt % added solvent, optionallyless than 1 wt % added solvent.

38. The method of item 36 to 37, wherein the aqueous phase of step a)comprise at least 3 grams protein per litre, optionally at least 5 g/L,optionally at least 8 g/L, optionally at least 10 g/L, optionally atleast 12 g/L, optionally between 5 to 25 g/L, optionally between 6 to 20g/L, optionally between 7 to 15 g/L, optionally between 8 to 12 g/L,optionally between 9 to 11 g/L.

39. The method of item 38, wherein 30 to 50% of the protein in theaqueous phase of step a) is PA.

40. The method of item 38, wherein 30 to 50% of the protein in theaqueous phase of step a) is PI.

41. The method of item 38, wherein at least 60% of the protein in theaqueous phase of step a) is PA or PI.

42. The method of item 38, wherein the aqueous phase of step a) compriseat least 50 mg/kg, optionally at least 75 mg/kg, optionally at least 100mg/kg, optionally at least 125 mg/kg, optionally at least 150 mg/kg,optionally at least 175 mg/kg, optionally at least 200 mg/kg, optionallyat least 250 mg/kg, optionally at least 300 mg/kg, optionally between50-400 mg/kg, optionally between 75-350 mg/kg, optionally between100-300 mg/kg glycoalkaloid.

43. The method of item 38, wherein the aqueous phase of step a) compriseat least 10 mg/kg, optionally at least 25 mg/kg, optionally at least 50mg/kg, optionally at least 125 mg/kg, optionally at least 170 mg/kg,optionally at least 225 mg/kg, optionally at least 300 mg/kg, optionallyat least 400 mg/kg, optionally at least 600 mg/kg, optionally between 25to 2000 mg/kg, optionally between 75 to 1500 mg/kg, optionally between200 to 1000 mg/kg phenolic compounds.

44. The method of item 36 to 43, wherein the aqueous phase consists ofthe aqueous solution liberated when disintegrating the said plantportion.

45. The method of item 36 to 44, wherein said disintegration includesshredding, crushing, squeezing or pressurizing the plant portion.

46. The method of item 36 to 45, wherein the plant portion is unpeeledbefore disintegration.

47. The method of item 36 to 46, wherein the tuber portion is a commonpotato.

48. The method of item 36 to 47, further comprising separating insolublesolid components, including suspended fibres, of the disintegrated plantportion from the liberated aqueous solution.

49. The method of any preceding item, wherein the ligand is a functionalgroup comprised in a polymer.

50. The method of item 49, wherein the functional group is selected fromone or more of hydrophobic, amphiphilic and hydrophilic groups,optionally an organic group.

51. The method of item 50, wherein the functional group is selected fromone or more of anionic groups, cationic groups, aryl groups, aromaticgroups, heteroaromatic groups and alkyl groups.

52. The method of item 51, wherein the functional group is selected fromone or more of carboxyl, sulphate, sulphonate, phosphate, phosphonate,silicate and silicone groups.

53. The method of item 52, wherein the functional group is selected fromone or more of aromatic sulfonic acids including polystyrene sulfonicacid (PSS), aromatic carboxylic acids, aromatic phosphonic acids

54. The method of items 49 to 53, wherein the ligand comprises anegative charge at pH 5, optionally at pH 4.5, optionally at pH 4.0,optionally at pH 3.5, optionally at pH 3.

55. The method of item 49 to 54, wherein the polymer has an averagemolecular size of at least 500 KDa, optionally at least 1500, optionallyat least 5.000 kDa, optionally between 5.000 to 10.000.000 KDa,optionally between 10.000 to 1.000.000 KDa, optionally between 10.000 to500.000 KDa, optionally between 10.000 to 200.000 KDa, optionallybetween 12.000 to 190.000 KDa. optionally between 200.000 to 400.000KDa.

56. The method of items 49 to 55, wherein the polymer is linear.

57. The method of items 49 to 55, wherein the polymer is branched.

58. The method of items 49 to 57, wherein the ligand is capable ofbinding to PA, PI, LipO or PPO by bonds selected from one or more ofhydrogen bonds, hydrophobic bonds, π-π (pi-pi) bonds and ionic bonds.

59. The method of items 49 to 58, wherein the polymer in aqueoussolution at pH 7 and 20° C. has a solubility of at least 50 g/L,optionally at least 100 g/L.

60. The method of items 49 to 59, wherein the polymer in aqueoussolution at a concentration of 50 g/L, at pH 7 and at 20° C. has a shearviscosity of less than 100000, optionally less than 50000, optionallyless than 25000 cP.

61. The method of items 49 to 60, wherein the polymer in aqueoussolution provides a liquid selected from a shear thinning liquid, aNewtonian liquid and a thixotropic liquid.

62. The method of items 49 to 61, wherein the polymer in aqueoussolution has an isoelectric point of less than pH 4.

63. The method of items 49 to 62, wherein the polymer in aqueoussolution has a net negative charge at pH less than 7, optionally lessthan pH 6, optionally less than pH 5, optionally less than pH 4.5,optionally less than pH 4.0

64. The method of items 49 to 63, wherein the polymer in aqueoussolution at pH 7 comprise at least 0.5 millimoles anionic groups pergram polymer, such as at least 2 millimoles anionic groups per grampolymer, such as at least 4 millimoles anionic groups per gram polymer,such as between 0.5 to 8 millimoles anionic groups per gram polymer,such as 1 to 7 millimoles anionic groups per gram polymer, such between2 to 6 millimoles anionic groups per gram.

65. The method of items 49 to 64, wherein the polymer is an inorganicpolymer, optionally comprising one or more organic groups.

66. The method of item 65, wherein the polymer comprises silicon,optionally in the form of a silicate or a silicone or a combinationthereof.

67. The method of item 66, wherein the polymer comprises a siliconederivatized with the functional group.

68. The method of items 49 to 67, wherein the polymer is solubilizedprior to contacting with the compounds selected from two or more of PA,PI, PPO, LipO, glycoalkaloid and phenolic compounds.

69. The method of items 49 to 68, wherein the polymer is added to theaqueous phase in the form of a preparation of the polymer in an aqueoussolvent.

70. The method of items 49 to 64, wherein the polymer is a naturallyoccurring polymer.

71. The method of item 70, wherein the polysaccharide is a naturallyoccurring polysaccharide.

72. The method of item 71, wherein the polysaccharide is selected fromone or more of chitosanate, carrageenanate, alginate, pectinate,agarose, xanthan gum, gum Arabic and dextran.

73. The method of items 49 to 64, wherein the polymer is a syntheticpolymer.

74. The method of item 73, wherein the polymer is a derivatizednaturally occurring polysaccharide.

75. The method of item 74, wherein the derivatized naturally occurringpolysaccharide is selected from one or more of dextran sulphate,carboxymethyl dextran, carboxymethylcellulose (CMC), carboxymethylstarch, cellulose sulphate, starch sulphate, cellulose phosphate,cellulose phosphonate, starch phosphate, starch phosphonate.

76. The method of item 73, wherein the synthetic polymer is selectedfrom one or more of polyacrylic acids (PAA), polymethacrylic acids(PMAA) and polyvinylsulfonic acids (PVS), silicones, and derivativeshereof.

77. The method of any preceding items, further comprising adsorbingcompounds selected from one or more of PA, PI, LipO, PPO, glycoalkaloidand phenolic compounds to a solid immobilized carrier, wherein theimmobilized solid carrier, optionally comprising a porous cross-linkedpolymer comprising a ligand capable of binding to the one or more of PA,PI, LipO, PPO, glycoalkaloid and phenolic compounds.

78. The method of item 77, wherein the polymer is the polymer of items49 to 67 or items 70 to 76.

79. The method of items 77 to 78, wherein the cross-linking isnon-covalent.

80. The method of items 77 to 78, wherein the cross-linking is covalent.

81. The method of items 77 to 80, wherein the immobilized carrier is inthe form of a porous powder or bead.

82. The method of items 77 to 81, wherein the immobilized carrier at theselected conditions adsorbs more PI than compounds selected from one ormore of PA, LipO and PPO.

83. The method of items 77 to 81, wherein the immobilized carrier at theselected conditions adsorbs more PA than compounds selected from one ormore of PI, LipO and PPO.

84. The method of item 77 to 81, wherein the immobilized carrier at theconditions adsorbs more PPO and LipO than compounds selected from one ormore of PA an PI.

85. The method of items 77 to 81, wherein the immobilized carrier at theconditions adsorbs more compounds selected from one or more of PI, LipOand PPO than PA.

86. The method of items 77 to 81, wherein the immobilized carrier at theconditions adsorbs more compounds selected from one or more of PI and PAthan PPO and LipO.

87. The method of items 77 to 81, wherein the immobilized carrier at theconditions adsorbs more compounds selected from one or more of PPO, LipOand PA than PI.

88. The method of items 77 to 81, wherein the immobilized carrier at theconditions adsorbs more compounds selected from one or more ofglycoalkaloid and phenolic compounds than compounds selected from one ormore of PPO, PA, LipO and PI.

89. The method of any preceding items, wherein the complex formationbetween the ligand and the compound selected from one or more of PA, PI,LipO, PPO, glycoalkaloid and phenolic compounds is carried out inaqueous phase at pH 7 or less, optionally pH 6 or less, optionally pH5.0 or less, optionally pH 4.6, optionally pH 4.5 or less, pH 2 or more,optionally pH 3 or more, optionally pH between 3.5 to 4, optionally pHbetween 5 to 6.

90. The method of any preceding items, wherein the complex formationbetween the ligand and the compound selected from one or more of PA, PI,LipO, PPO, glycoalkaloid and phenolic compounds is carried out inaqueous phase having a conductivity of at least 5 mS/cm, optionally atleast 7 mS/cm, optionally at least 9 mS/cm, optionally at least 10mS/cm, optionally at least 12 mS/cm, optionally between 5-20 mS/cm,optionally between 8-15 mS/cm, optionally between 9-13 mS/cm.

91. The method of any preceding items, wherein the complex formationbetween the ligand and the compound selected from one or more of PA, PI,LipO, PPO, glycoalkaloid and phenolic compounds is carried out inaqueous phase having a temperature of between 4° C. to 50° C.,optionally between 10° C. to 45° C., optionally between 12° C. to 40°C., optionally between 15° C. to 35° C.

92. The method of any preceding items, wherein the complex formationbetween the ligand and the compound selected from one or more of PA, PI,LipO, PPO, glycoalkaloid and phenolic compounds is carried out inaqueous phase having a polymer concentration between 0.1 to 50 g/L,optionally between 0.2 to 20 g/L, optionally between 0.2 to 5 g/L,optionally between 0.2 to 3 g/L, optionally between 0.2 to 2 g/L,optionally between 0.5 to 3 g/L optionally between 0.5 to 2 g/L,optionally between 1.0 to 10 g/L, optionally between 1.0 to 5 g/L,optionally between 1.0 to 3 g/L.

93. The method of any preceding items, wherein the complex formationbetween the ligand and the compound selected from one or more of PA, PI,LipO, PPO is carried out in aqueous phase having a protein concentrationcorresponding to the sum of PA, PI, LipO and PPO of at least 2 g/L g/L.optionally at least 4 g/L, optionally at least 7 g/L, optionally atleast 8 g/L, optionally at least 9 g/L, optionally between 2 to 22 g/L,optionally between 3 to 20 g/L, optionally between 5 to 15 g/L,optionally between 6 to 12 g/L, optionally between 7 to 11 g/L.

94. The method of any preceding items, wherein the complex formedbetween the ligand and the compound selected from one or more of PA, PI,LipO and PPO comprise between 0.01 mg to 0.5 mg, optionally 0.03 mg to0.3 mg, optionally 0.05 mg to 0.3 mg complexed polymer per mg complexedprotein.

95. The method of any preceding items, wherein the complex between themobile solubilized ligand and the compound separates from the aqueoussupernatant by changing the physico-chemical conditions in the aqueousphase to reduce the solubility of the complex in the aqueous phase.

96. The method of item 95, wherein the changing of the physico-chemicalconditions comprises adjusting the pH to between 2 to 6 preferably tobetween 3 to 6, optionally between 3.5 to 5.5, optionally between 4.0 to5.0

97. The method of item 96, wherein the changing of the physico-chemicalconditions comprises adjusting the pH to between 3.5 to 4.

98. The method of item 96, wherein the changing of the physico-chemicalconditions comprises adjusting the pH to between 5 to 6.

99. The method of item 95, wherein the changing of the physico-chemicalconditions comprises adjusting the conductivity, optionally by addingsalts such as sodium chloride or calcium chloride.

100. The method of item 95, wherein the changing of the physico-chemicalconditions comprises adding an organic solvent to the aqueous phase,optionally ethanol.

101. The method of item 95, wherein the changing of the physico-chemicalconditions comprises adjusting the temperature.

102. The method of any preceding items, wherein the precipitated complexis separated from the aqueous supernatant phase by a mechanicalseparation process selected from one or more of membrane separation andcentrifugal separation.

103. The method of item 102, wherein the membrane separation process isa continuous membrane separation process, optionally a cross flow, adynamic or a tangential flow membrane separation process.

104. The method of item 102 or 103, wherein the membrane separationprocess comprise use of a membrane module selected from one or more oftubular membranes, hollow fibre membranes, spiral wound membranes andplate and frame membranes.

105. The method of item 102 to 104, wherein the membrane comprises amaterial selected from one or more of ceramics, metal, artificialpolymer and natural polymer.

106. The method of item 105, wherein the membrane is a polyether sulfonemembrane or an esterified cellulose membrane.

107. The method of item 104, wherein the membrane module is a hollowfibre membrane and wherein the separation process is performed at thefollowing conditions:

pH of the aqueous phase of between 2 to 6.

Feed pressure of between 9 to 15 psi

Backwash pressure of between 9 to 15 psi.

Temperature of the aqueous phase of between 5° C. to 30° C.

108. The method of item 104, wherein the membrane module is a spiralwound membrane and wherein the separation process is performed at thefollowing conditions:

pH of the aqueous phase of between 2 to 6.

Feed pressure of less than 120 psi

Backwash pressure of between 20 to 40 psi.

Temperature of the aqueous phase of between 5° C. to 45° C.

109. The method of item 104, wherein the membrane module is a ceramictubular membrane and wherein the separation process is performed at thefollowing conditions:

pH of the aqueous phase of between 3 to 7.

Feed pressure of 60 to 100 psi

Backwash pressure of between 10 to 30 psi.

Temperature of the aqueous phase of between 5° C. to 40° C.

110. The method of item 102 to 109 further comprising a diafiltrationstep.

111. The method of item 102, wherein the complex is separated fromaqueous supernatant phase by centrifugal separation.

112. The method of item 111, wherein the centrifugation is performed atan acceleration between 500 to 5000 G, optionally between 1000 to 4000G, optionally between 1500 to 3000 G.

113. The method of items 111 or 112, wherein the centrifugal separationis performed by a centrifuge or a liquid cyclone separator.

114. The method of item 113, wherein the centrifugation is a continuousprocess and the retention time is less than 30 min, optionally less than15 min, optionally less than 10 min, optionally less than 5 min,optionally less than 3 min, optionally less than 2 min.

115. The method of item 114, wherein the flow rate to the centrifuge ismore than 50 L/min, optionally more than 100 L/min, optionally more than200 L/min, optionally more than 300 L/min, optionally more than 400L/min, optionally more than 500 L/min, optionally between 50 to 1000L/min, optionally between 100-750 L/min, optionally between 75 to 400L/min.

116. The method of items 111 or 112, wherein the liquid cycloneseparator is a multistage separator comprising at least two serialhydrocyclones, optionally at least three serial hydrocyclones,optionally at least four serial hydrocyclones.

117. The method of item 102 to 116, wherein the mechanical separationprocess is capable of retaining compounds having a size of more than 50kDa, optionally having a size of more than 75 kDa, optionally having asize of more than 100 kDa, optionally having a size of more than 125kDa, optionally having a size of more than 150 kDa.

118. The method of item 2, further comprising mixing the precipitatedcomplex with a substance capable of extracting one or more compoundsselected from PA, PI, LipO, PPO, glycoalkaloid and phenolic compoundsfrom the complex and isolating the one or more compounds selected fromPA, PI, LipO, PPO, glycoalkaloid and phenolic compounds by a mechanicalseparation process concentrating the one or more compounds selected fromPA, PI, LipO, PPO, glycoalkaloid and phenolic compounds in theretentate.

119. The method of item 118, wherein the substance is an aqueoussolvent.

120. The method of item 119, wherein the aqueous solvent has anincreased pH and optionally an increased conductivity compared to theaqueous supernatant phase from which the complex separated.

121. The method of item 120, wherein the aqueous solvent has a pHbetween 7 to 14 and optionally a conductivity between 10 mS/cm to 200mS/cm.

122. The method of item 118, wherein the substance is a solid substanceincreasing the pH in the isolated complex.

123. The method of item 122, wherein the solid substance is selectedfrom one or more of oxides, hydroxides, phosphates, carboxylates andammonia, optionally in the form of salts of ammonium or metals, such assodium, potassium, calcium, magnesium.

124. The method of items 118 to 123, wherein the mechanical separationprocess is a process of items 102 to 117.

125. The method of any preceding items, further comprising at least onestep of selective elution.

126. The method of item 125, wherein the selective elution step releasesone or more compounds associated with the isolated complex, optionallyby entrapment, by being bound to a moiety of the ligand or complexedcompound or by being comprised in liquid remaining in the complex.

127. The method of items 125 to 126, wherein the released compound isselected from one or more of glycoalkaloid, phenolic compounds, PPO, PA,LipO, PI and the ligand.

128. The method of items 125 to 126, wherein the released compound isselected from one or more of glycoalkaloid, LipO, phenolic compounds,PPO and the ligand.

129. The method of items 125 to 127, wherein the released compound isselected from one or more of PA and PI.

130. The method of items 125 to 127, wherein the released compound isselected from one or more of PPO, PA and PI.

131. The method of items 125 to 130 wherein the selective elution isperformed by contacting the isolated complex with a solvent whichreleases the one or more compounds.

132. The method of items 131, wherein the solvent is an aqueous solvent,optionally wherein conditions are selected from pH 1 to pH 6 and aconductivity between 1 mS/cm to 300 mS/cm optionally from pH 2 and aconductivity between 10 mS/cm to 200 mS/cm, optionally from pH 3 to pH4.5 and a conductivity between 50 mS/cm and 100 mS/cm, optionally frompH 4.6 to pH 5 and a conductivity between 25 mS/cm to 250 mS/cm.

133. The method of items 131 to 132, wherein the solvent comprise anorganic solvent selected from one or more of alcohols, glycols, esters,ethers, amines, aromatic acids, alkyl acids such as methanol, ethanol,propanol, polyethylene glycol, (PEG), propylene glycol (PG),monopropylene glycol (MPG), glycerol, benzoic acid, hexanoic acid,octanoic acid and derivatives of these.

134. The method of item 131 to 133, wherein the solvent comprise asurfactant selected from one or more of non-ionic surfactants, anionicsurfactants, cationic surfactants, zwitterionic or amphotericsurfactants.

135. The method of item 134, wherein the surfactant is selected from oneor more of sodium dodecyl sulphate, Tween 20, cetyl trimethyl ammoniumbromide.

136. The method of item 131, wherein the eluted compound is PI and thesolvent is an aqueous solution of sodium chloride at a concentrationbetween 0.2 M to 2 M, optionally a concentration between 0.3 M to 1 M,optionally a concentration between 0.4 M to 0.8 M, optionally aconcentration between 0.45 M to 0.65 M.

137. The method of items 131 to 136 wherein the aqueous solvent furthercomprises a buffer having a pH between pH 1 to pH 4.5, optimally a pHbetween 2 to pH 4.0, optionally a pH between pH 2.5 to pH 3.6.

138. The method of items 131 to 137, wherein the buffer is selected fromone or more of acetate, citrate, sulphate, phosphate.

139. The method of items 131 to 138, wherein the aqueous solventcomprises a salt, optionally selected from alkali or earth alkali metalsalts of chloride, nitrate, nitrite sulphate, sulphite, phosphate,acetate or citrate.

140. The method of any preceding items, further comprising subjectingthe isolated compound(s) to microbial control step.

141. The method of item 140, wherein the microbial control stepcomprises adding an agent selected from bactericidal agents,bacteriostatic agent, fungicidal agents and fungistatic agents.

142. The method of item 140, wherein the microbial control stepcomprises one or more operations selected from heating, irradiating andfiltering.

143. The method of any preceding items, further comprising a step ofseparating the compound selected from one or more of PA, PI, LipO andPPO from the ligand.

144. The method of any preceding items, further comprising a step of,optionally irreversibly, inactivating the one or more of PA, PI, LipOand PPO.

145. The method of item 144, wherein the one or more of PA, PI, LipO andPPO is inactivated by denaturation, optionally thermal or solventdenaturation.

146. The method of any preceding items, further comprising forming theisolated compound(s) into a formulation selected from powders, pastes,slurries or liquids.

147. The method of item 146, wherein the formulation is a powderselected from a dried product, a spray dried product, a prilled product,a layered product, an absorbed core product, an extruded product and amixer granulated product.

148. The method of items 146 or 147, wherein the water activity, aw, ofthe formulation is below 0.9, optionally below 0.7, optionally below0.6.

149. The method of items 146 to 148, comprising reducing the wateractivity by adding a mono- or disaccharide to the formulation.

150. The method of item 149, wherein the mono- or disaccharide isselected from one or more of glucose, fructose, sucrose and lactose.

151. The method of items 146 to 148, wherein the water activity isreduced by adding a dextrin derived from starch.

152. The method of any preceding items, further comprising stabilisingthe one or more of PA, PI, LipO and PPO by adding a protein stabilizingagent, optionally selected from one or more antioxidants, reducingagents, PVP, PVA and PEG.

153. The method of any preceding items, wherein the formation of thecomplex is carried out in an, optionally thermos controlled, andagitated reactor having a volume of at least 500 L, optionally at least1000 L, optionally at least 4000 L, optionally at least 8000 Loptionally at least 15000 L optionally at least 25000 L.

154. The method of item 153, wherein the reactor is a continuous reactoror a batch reactor.

155. The method of items 153 to 154, wherein the agitation is selectedfrom stirring, shaking, rotation, pumping and vibrating.

156. The method of items 153 to 155, wherein the thermal controlincludes a heating source selected from steam, electricity and fuel andoptionally a cooling source selected from liquid or gas cooling.

157. The method of any preceding item wherein a compound selected in thefirst group is deselected in the second group.

158. The method of any preceding item, wherein the aqueous phase of stepa) comprises a compound selected from one or more of PA, PI, PPO and acompound selected from one or more of glycoalkaloid, LipO and phenoliccompounds.

159. A method for isolating one or more of glycoalkaloid, LipO andphenolic compounds said method comprising:

a) providing an aqueous phase comprising one or more of glycoalkaloid,LipO and phenolic compounds and at least one protein;

b) contacting the aqueous phase with a mobile solubilized ligand atphysico-chemical conditions allowing formation of a complex between theligand and the protein;

c) allowing the complex to separate from the aqueous supernatant phase,optionally by changing said physico-chemical conditions in thecomposition to reduce the solubility of the complex; and

d) isolating the one or more of glycoalkaloid, LipO and phenoliccompounds comprised in the aqueous phase from the complex.

160. A method for isolating one or more of glycoalkaloid, LipO andphenolic compounds said method comprising:

a) providing an aqueous phase comprising one or more of glycoalkaloidLipO and phenolic compounds and at least one protein;

b) contacting the aqueous phase with a mobile solubilized ligand atphysico-chemical conditions allowing formation of a complex between theligand and the one or more of glycoalkaloid, LipO and phenoliccompounds;

c) allowing the complex to separate from the aqueous supernatant phase,optionally by changing said physico-chemical conditions in thecomposition to reduce the solubility of the complex; and

d) isolating the one or more of glycoalkaloid, LipO and phenoliccompounds comprised in the complex.

161. The method of items 159 or 160, wherein the mobile solubilizedligand is selected from one or more of silicates and silicones.

162. A composition comprising one or more of patatin protein (PA),protease inhibitor protein (PI), lipoxygenase (LipO), polyphenol oxidase(PPO), glycoalkaloid and phenolic compounds obtainable from the methodof items 1 to 158.

163. The composition of item 162, comprising one or more of lipoxygenase(LipO), glycoalkaloid and phenolic compounds.

164. The composition of item 162, comprising one or more of PA, PI andPPO.

165. The composition of item 162, further comprising the ligand of items49 to 54.

166. The composition of item 166, comprising at least 25%, optionally atleast 50%, optionally at least 75% of the polymer contained in thecomplex of item 1.

167. The composition of item 162, wherein the composition is an additivefor one or more of foods, animal feeds, pet foods, beverages, cosmetics,pharmaceuticals, nutraceuticals, dietary supplements and fermentations.

168. The composition of item 167, wherein the additive is an additive toa food or beverage selected from one or more of meats, confectionary,bread, dairy, ready-to-eat food and sports food and drinks.

169. The composition of item 167, wherein the additive is an additive toanimal feed selected from poultry feed, ruminants feed, pig feed, horsefeed, fish feed and insect feed.

170. The composition of item 167, wherein the additive is an additive toa pet food selected from canine or feline pet foods.

171. The composition of item 167, wherein the additive is an additive toa cosmetic selected from lotions, creams, gels, ointments, soaps,shampoos, conditioners, antiperspirants, deodorants, mouth wash, contactlens products and foot bath products.

172. The composition of item 167, wherein the additive is an additive toa nutraceutical.

173. The composition of item 167, wherein the additive is an additive tois an additive to a dietary supplement, optionally to a proteinsupplement or to a senior nutrition product.

174. The composition of item 167, wherein the additive is an additive toa fermentation selected from a bacterial fermentation, a fungalfermentation or a yeast fermentation.

175. The composition of items 162 to 166, wherein the composition is afood or beverage composition

176. The composition of items 162 to 166, wherein the composition is ananimal feed composition.

177. The composition of items 162 to 166, wherein the composition is apet food composition.

178. The composition of items 162 to 166, wherein the composition is acosmetic composition.

179. The composition of item 178, wherein the cosmetic composition is acomposition comprising glycoalkaloid, optionally for use as anexfoliant.

180. The composition of items 162 to 166, wherein the composition is apharmaceutical composition.

181. The composition of item 180, wherein the pharmaceutical compositionis a composition comprising glycoalkaloid for use as a medicament.

182. The composition of item 181 for use as a medicament for treatingcancer.

183. The composition of items 162 to 166, wherein the composition is anutraceutical composition.

184. The composition of items 162 to 166, wherein the composition is adietary supplement.

185. The composition of items 162 to 166, wherein the composition is afermentation broth.

186. A composition, comprising a natural or synthetic polymer havingaromatic or heteroaromatic acid ligands covalently attached.

187. The composition of item 186, wherein the polymer is soluble inaqueous solvent above pH 6.

188. The composition of items 186 or 187, wherein the polymer isinsoluble below pH 5.9. optionally below pH 5.5, optionally below pH5.0, optionally below pH 4.8, optionally below pH 4.5, optionally belowpH 4.2, optionally below pH 4.0, optionally below pH 3.5

189. The composition of items 186 to 188, wherein the polymer is asoluble starch reacted with a bifunctional reagent for attachment of theligands

190. The composition of item 189, wherein the bifunctional reagent ischosen from one or more of epichlorohydrin, allyldiglycidyl ether, allylbromide and divinyl sulfone.

191. The composition of item 186 to 190, wherein the aromatic orheteroaromatic acid is chosen from the group of hydroxybenzoic acid,aminobenzoic acid, mercaptobenzoic acid and derivatives hereof.

192. A container comprising a composition or a product of any of items162 to 191.

193. Use of the composition of item 162 to 174, in a process forproviding one or more functions selected from foam control, emulsioncontrol, control of proteolytic activity, nutrition, gelation,solubility, organoleptic improvement, allergenicity reduction andoxidation.

194. A method for isolating one or more proteins comprising contacting acomposition, optionally an aqueous composition, comprising the one ormore proteins with a water-soluble silicon containing anionic polymercapable of binding to the protein; optionally adjusting the conditionsin the composition to promote binding between the protein(s) and thepolymer and causing the bound proteins to separate from the composition,optionally by precipitation and isolating the separated boundprotein(s), optionally comprising one or more selective elution steps toachieve one or more isolated protein fractions, optionally separatedfrom the polymer.

195. The method of item 194, wherein the polymer is a solubilizedsilicon containing anionic polymer.

196. The method of item 194, wherein the polymer is dissolved in theaqueous composition under conditions that does not lead to formation ofsubstantial amounts of separated proteins until the conditions have beenadjusted to effect separation.

197. The method of item 196, wherein the polymer is dissolved in theaqueous composition at pH 7 or higher, optionally at pH 8 or higher,optionally at pH 9 or higher, optionally at pH 10 or higher.

198. The method of items 194 to 197, wherein precipitation of proteinbound to the silicon containing polymer is caused by adjusting pH tobelow pH 8, optionally to below 7, optionally to below pH 6.5,optionally to a pH between 1 to 9, optionally to a pH between 2 to 8,optionally to a pH between 3 to 7, optionally to a pH between 3.5 to6.5, optionally to a pH between 4.5 to 6.5, optionally to a pH between5.5 to 6.5.

199. The method of items 194 to 198, wherein the polymer is a silicate,optionally a metal silicate.

200. The method of item 199, wherein the silicate is selected from thegroup of sodium silicate, potassium silicate, ammonium silicates,quaternary ammonium silicates and mixtures of these.

201. The method of item 200, wherein the silicate is a water glass(sodium metasilicate).

202. The method of items 194 to 198, wherein the silicon containingpolymer comprise silicone moieties, optionally in a mixture withsilicates.

203. The method of item 202, wherein the silicone moieties comprise anorganic functional group capable of binding to proteins.

204. The method of item 202, wherein the organic functional groupcomprise a hydrophobic group such as a C2-C12 branched or un-branchedalkyl group, an aromatic or heteroaromatic ring system or a combinationof these.

205. The method of item 202, wherein the organic functional groupcomprise one or more anionic groups, one or more cationic groups or acombination of these.

206. The method of items 202 to 205, wherein the silicone moieties arederived from the a reactive silane, optionally glycidoxypropyl or allylsilane, optionally 3-glycidoxypropyldimethoxymethylsilane,3-glycidoxypropyldimethylethoxysilane,(3-glycidyloxypropyl)trimethoxysilane, allyltrimethoxysilane,allyltriethoxysilane.

207. The method of items 202 to 206, wherein the silicone moieties aremixed with silicates in a molar ratio silicone:silicate in the range of0.001 to 0.99, optionally 0.01 to 0.90, optionally 0.02 to 0.8,optionally 0.03 to 0.7, optionally 0.05 to 0.6, optionally 0.07 to 0.5,optionally 0.1 to 0.4, optionally 0.05 to 0.30, optionally 0.1 to 0.2.

208. A method for isolating a first group of compounds selected from oneor more of patatin protein (PA), protease inhibitor protein (PI),lipoxygenase (LipO) and polyphenol oxidase (PPO) from a second group ofcompounds selected from one or more of PA, PI, LipO, PPO, pectin, lipid,glycoalkaloid and phenolic compounds said method comprising

a) providing an aqueous phase comprising compounds selected from two ormore of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid and phenoliccompounds of which at least one compound is selected from PA, PI, LipOand PPO;

b) performing one or more steps to reduce the concentration of solaninein the dry matter of the aqueous phase with at least 15 percent, such asat least 20%, such as at least 25% and to achieve an optical density at620 nm of the remaining aqueous phase of less than 0.7; such as lessthan 0.5; such as less than 0.3; such as less than 0.2; such as lessthan 0.1;

c) contacting the remaining aqueous phase with a mobile solubilizedligand at physico-chemical conditions allowing formation of a complexbetween the ligand and the compounds selected from one or more of PA,PI, LipO and PPO;

d) allowing the complex to separate from the aqueous supernatant phase,optionally by changing said physico-chemical conditions in thecomposition to reduce the solubility of the complex; and

e) isolating the complex separated from the aqueous phase.

209. A method for isolating a first group of compounds selected from oneor more of patatin protein (PA), protease inhibitor protein (PI),lipoxygenase (LipO) and polyphenol oxidase (PPO) from a second group ofcompounds selected from one or more of PA, PI, LipO, PPO, pectin, lipid,glycoalkaloid and phenolic compounds said method comprising

a) providing an aqueous phase comprising compounds selected from two ormore of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid and phenoliccompounds of which at least one compound is selected from PA, PI, LipOand PPO;

b) performing one or more steps to reduce the concentration of solaninein the dry matter of the aqueous phase with at least 15 percent, such asat least 20%, such as at least 25% and to achieve an optical density at620 nm of the remaining aqueous phase of less than 0.7; such as lessthan 0.5; such as less than 0.3; such as less than 0.2; such as lessthan 0.1;

f) adjusting pH of the remaining aqueous phase (from step b)) to allowthe formation of a precipitate comprising PA; and

g) isolating the precipitate from the aqueous phase.

210. A method for isolating a first group of compounds selected from oneor more of patatin protein (PA), protease inhibitor protein (PI),lipoxygenase (LipO) and polyphenol oxidase (PPO) from a second group ofcompounds selected from one or more of PA, PI, LipO, PPO, pectin, lipid,glycoalkaloid and phenolic compounds said method comprising

a) providing an aqueous phase comprising compounds selected from two ormore of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid and phenoliccompounds of which at least one compound is selected from PA, PI, LipOand PPO;

b) performing one or more steps to reduce the concentration of solaninein the dry matter of the aqueous phase with at least 15 percent, such asat least 20%, such as at least 25% and to achieve an optical density at620 nm of the remaining aqueous phase of less than 0.7; such as lessthan 0.5; such as less than 0.3; such as less than 0.2; such as lessthan 0.1; and

h) subjecting the remaining aqueous phase (from step b)) to a membranefiltration process separating at least one of PA and PI in the retentatefrom at least one of PA, PI, LipO, PPO, pectin, lipid, glycoalkaloid andphenolic compounds in the permeate.

211. A method for reducing turbidity of an aqueous phase comprisingcompounds selected from two or more of PA, PI, PPO, LipO, pectin, lipid,glycoalkaloid and phenolic compounds of which at least one compound isselected from PA, PI, LipO and PPO;

-   -   a) providing an aqueous phase comprising compounds selected from        two or more of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid        and phenolic compounds of which at least one compound is        selected from PA, PI, LipO and PPO;    -   b) contacting the aqueous phase with a soluble silicate at a pH        in the range of 3-10 and optionally, a divalent or trivalent        metal ion allowing formation of an insoluble precipitate        comprising said silicate and one or more the compounds selected        from LipO, PPO, pectin, lipid, glycoalkaloid and phenolic        compounds, and optionally, a divalent or trivalent metal ion,        said insoluble precipitate is subsequently removed from the        aqueous phase by physical means;

thereby obtaining an aqueous phase having reduced turbidity compared toan untreated aqueous phase.

212. A method for isolating a first group of compounds selected from oneor more of patatin protein (PA), protease inhibitor protein (PI),lipoxygenase (LipO) and polyphenol oxidase (PPO) from a second group ofcompounds selected from one or more of PA, PI, LipO, PPO, pectin, lipid,glycoalkaloid and phenolic compounds said method comprising

-   -   a) providing an aqueous phase comprising compounds selected from        two or more of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid        and phenolic compounds of which at least one compound is        selected from PA, PI, LipO and PPO;    -   b) contacting the aqueous phase with a soluble silicate at a pH,        in the range of 3-10 and optionally, a divalent or trivalent        metal ion allowing formation of an insoluble precipitate        comprising said silicate and one or more the compounds selected        from LipO, PPO, pectin, lipid, glycoalkaloid and phenolic        compounds, and optionally, a divalent or trivalent metal ion,        said insoluble precipitate is subsequently removed from the        aqueous phase by physical means;    -   c) contacting the remaining aqueous phase with a mobile        solubilized ligand at physico-chemical conditions allowing        formation of a complex between the ligand and the compounds        selected from one or more of PA, PI, LipO and PPO;    -   d) allowing the complex to separate from the aqueous supernatant        phase, optionally by changing said physico-chemical conditions        in the composition to reduce the solubility of the complex; and    -   e) isolating the complex separated from the aqueous phase.    -   OR    -   f) adjusting pH of the remaining aqueous phase (from step b)) to        allow the formation of a precipitate comprising PA;    -   g) isolating the precipitate from the aqueous phase    -   OR    -   h) subjecting the remaining aqueous phase (from step b)) to a        membrane filtration process separating at least one of PA and PI        in the retentate from at least one of PA, PI, LipO, PPO, pectin,        lipid, glycoalkaloid and phenolic compounds in the permeate

213. A method according to any of claims 211-212, wherein the silicateconcentration is in the range of 0.2-5 g/L, preferably in the range of0.5-3 g/L

214. A method according to any of claims 211-213, wherein silicate issodium silicate.

215. A method according to any of claims 211-214, wherein theconcentration of the divalent or trivalent metal ion in the aqueousphase is between 2-100 mM, preferably in the range of 5-25 mM

216. A method according to any of claims 211-215, wherein the divalentor trivalent metal ion is a calcium, magnesium or aluminum ion.

217. A method according to any of claims 211-215, wherein the physicalmeans in step b) is centrifugation and the supernatant is subsequentlyremoved.

218. A method according to claim 217, wherein the precipitate is washedby resuspension in water and pH adjusted to 3.0 with hydrochloric acidand centrifuged and the supernatant removed.

219. A method according to claim 218, wherein the washed precipitate issuspended in water and pH is slowly adjusted to pH 7-10 with 1 M NaOH.

220. A method for isolating a first group of compounds selected from oneor more of patatin protein (PA), protease inhibitor protein (PI),lipoxygenase (LipO) and polyphenol oxidase (PPO) from a second group ofcompounds selected from one or more of PA, PI, LipO, PPO, pectin, lipid,glycoalkaloid and phenolic compounds said method comprising

a) providing an aqueous phase comprising compounds selected from two ormore of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid and phenoliccompounds of which at least one compound is selected from PA, PI, LipOand PPO;

b) performing one or more steps to reduce the concentration of solaninein the dry matter of the aqueous phase with at least 15 percent, such asat least 20%, such as at least 25% and to achieve an optical density at620 nm of the remaining aqueous phase of less than 0.7; such as lessthan 0.5; such as less than 0.3; such as less than 0.2; such as lessthan 0.1;

c) contacting the remaining aqueous phase with a mobile solubilizedligand at physico-chemical conditions allowing formation of a complexbetween the ligand and the compounds selected from one or more of PA,PI, LipO and PPO;

d) allowing the complex to separate from the aqueous supernatant phase,optionally by changing said physico-chemical conditions in thecomposition to reduce the solubility of the complex; and

e) isolating the complex separated from the aqueous phase.

221. A method for isolating a first group of compounds selected from oneor more of patatin protein (PA), protease inhibitor protein (PI),lipoxygenase (LipO) and polyphenol oxidase (PPO) from a second group ofcompounds selected from one or more of PA, PI, LipO, PPO, pectin, lipid,glycoalkaloid and phenolic compounds said method comprising

a) providing an aqueous phase comprising compounds selected from two ormore of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid and phenoliccompounds of which at least one compound is selected from PA, PI, LipOand PPO;

b) performing one or more steps to reduce the concentration of solaninein the dry matter of the aqueous phase with at least 15 percent, such asat least 20%, such as at least 25% and to achieve an optical density at620 nm of the remaining aqueous phase of less than 0.7; such as lessthan 0.5; such as less than 0.3; such as less than 0.2; such as lessthan 0.1;

f) adjusting pH of the remaining aqueous phase (from step b)) to allowthe formation of a precipitate comprising PA; and

g) isolating the precipitate from the aqueous phase.

222. A method for isolating a first group of compounds selected from oneor more of patatin protein (PA), protease inhibitor protein (PI),lipoxygenase (LipO) and polyphenol oxidase (PPO) from a second group ofcompounds selected from one or more of PA, PI, LipO, PPO, pectin, lipid,glycoalkaloid and phenolic compounds said method comprising

a) providing an aqueous phase comprising compounds selected from two ormore of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid and phenoliccompounds of which at least one compound is selected from PA, PI, LipOand PPO;

b) performing one or more steps to reduce the concentration of solaninein the dry matter of the aqueous phase with at least 15 percent, such asat least 20%, such as at least 25% and to achieve an optical density at620 nm of the remaining aqueous phase of less than 0.7; such as lessthan 0.5; such as less than 0.3; such as less than 0.2; such as lessthan 0.1; and

h) subjecting the remaining aqueous phase (from step b)) to a membranefiltration process separating at least one of PA and PI in the retentatefrom at least one of PA, PI, LipO, PPO, pectin, lipid, glycoalkaloid andphenolic compounds in the permeate.

223. A method according to any of claims 211-222, wherein the pH of theaqueous phase in step b) is adjusted to a pH in the range of 5-9,preferably in the range of 6-8.

224. A method according to any of claims 211-223, wherein the formationof an insoluble precipitate in step b) is made by incubating the aqueousphase for less than 120 min, preferably less than 60 min, preferablyless than 30 min, preferably less than 15 min.

225. A method according to any of claims 211-224, wherein the formationof an insoluble precipitate in step b) is made by incubating the aqueousphase at 15-50° C., preferably at 20-45° C., preferably at 22-40° C.,preferably at 25-35° C.

226. A method for isolating a first group of compounds selected from oneor more of patatin protein (PA), protease inhibitor protein (PI),lipoxygenase (LipO) and polyphenol oxidase (PPO) from a second group ofcompounds selected from one or more of PA, PI, LipO, PPO, pectin, lipid,glycoalkaloid and phenolic compounds said method comprising

a) providing an aqueous phase comprising compounds selected from two ormore of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid and phenoliccompounds of which at least one compound is selected from PA, PI, LipOand PPO;

b) adjusting pH of the aqueous phase to allow the formation of aprecipitate comprising at least 10% of the PA initially present in theaqueous phase and to achieve an optical density at 620 nm of theremaining aqueous phase of less than 0.7;

c) isolating the precipitate from the aqueous phase

d) isolating PI from the remaining aqueous phase (from step c)).

227. The method according to claim 226, wherein the optical density at620 nm of the remaining aqueous phase in step b) is less than 0.5; suchas less than 0.3; such as less than 0.2; such as less than 0.1; such asless than 0.07

228. The method according to claims 226-227, wherein the concentrationof solanine in the dry matter of the remaining aqueous phase in step b)reduced with at least 5 percent.

229. The method according to claims 226-228, wherein the aqueous phasein step a) is potato fruit juice obtained from industrial manufacture ofpotato starch.

230. The method according to claims 226-229, wherein the fruit juice isfurther treated in a defoamer to substantially reduce the amount of foamin the fruit juice.

231. The method according to claims 226-230, wherein the fruit juice hasbeen treated to substantially reduce the amount of insoluble substancesin the fruit juice prior to pH adjustment in step b)

232. The method according to claims 226-231, wherein the pH adjustmentin step b) is performed less than 200 minutes after the fruit juice hasbeen released from the potatoes, such as less than 150 minutes, such asless than 100 minutes, such as less than 60 minutes, such as less than30 minutes, such as less than 20 minutes, such as less than 10 minutes,such as less than 5 minutes after the fruit juice has been released fromthe potatoes.

233. The method according to claims 226-232, wherein the fruit juice ispH adjusted by an in-line mixing with an acid.

234. The method according to claims 226-233, wherein the fruit juice hasbeen added an antioxidant, such as sodium bisulfite or sodium sulfite.

235. The method according to claims 226-234, wherein the fruit juice hasa total true protein concentration of at least 5 g/L such at least 6g/L, such as at least 7 g/L, such as at least 8 g/L fruit juice.

236. The method according to claims 226-235, wherein the aqueous phasein step b) is adjusted to a pH below pH 5.5, such as below pH 5.0, suchas below pH 4.5, such as below pH 4.0

237. The method according to claims 226-236, wherein the aqueous phasein step b) is adjusted to a pH in the range of pH 1-5.5, such as in therange of pH 1.5-5.0, such as in the range of 2.0-4.5, such as in therange of pH 2.0-3.8, such as in the range of pH 2.5-3.5.

238. The method according to claims 226-237, wherein the aqueous phasein step b) is adjusted to a pH in the range of pH 3.0-5.0, such as inthe range of pH 3.0-4.5, such as in the range of pH 3.3-4.2, wherebyLipoxygenase in the resulting precipitate is separated from PI in theremaining aqueous phase.

239. The method according to claims 226-238, wherein the aqueous phasein step b) has a temperature in the range of 20-62 degrees Celsius, suchas in the range of 24-48 degrees Celsius, such as in the range of 30-45degrees Celsius, such as in the range of 35-45 degrees Celsius, such asin the range of 41-60 degrees Celcius, such as in the range of 45-58degrees Celcius, such as in the range of 48-58 degrees Celcius.

240. The method according to claims 226-239, wherein the precipitate instep b) comprise at least 10% of the PA initially present in the aqueousphase, such as at least 20%, such as at least 30%, such as at least 50%,such as at least 70%, such as at least 85%, such as at least 90% of thePA initially present in the aqueous phase.

241. The method according to claims 226-240, wherein the isolation ofthe precipitate from the aqueous phase in step c is performed using adecanter centrifuge.

242. The method according to claims 226-241, wherein the isolatedprecipitate in step c) is further treated to produce a protein powder asan animal feed product. In one embodiment, the precipitate is washedwith an aqueous solution of an acid and dried.

243. The method according to claims 226-242, wherein the optimalbusiness model for utilizing potato fruit juice is the combinedproduction of a PA product not intended for use as a functional proteinand a highly functional PI product, rather than the production of both afunctional PA and a functional PI product.

244. The method according to claims 226-243, wherein the isolatedprecipitate in step c) contains less than 50%, such as less than 40%,such as less than 30%, such as less than 20%, such as less than 10%functional PA.

245. The method according to claims 226-244, wherein the isolatedprecipitate in step c) contains less than 50%, such as less than 40%,such as less than 30%, such as less than 20%, such as less than 10% PAbeing soluble by suspension of the precipitate in an aqueous phosphatebuffer at 2% dry matter and at pH 7.0.

246. The method according to claims 226-245, wherein the isolatedprecipitate in step c) is further treated to produce a protein powder asa human nutritional food product. In one embodiment, the precipitate iswashed with an aqueous solution of an acid and dried.

247. The method according to claims 226-246, wherein the isolatedprecipitate in step c) is further treated to produce a protein powder asa human functional protein ingredient product. In one embodiment, theprecipitate is washed with an aqueous solution of an acid and dried.

248. The method according to claims 226-247, wherein the isolatedprecipitate in step c) is dissolved by adjusting pH to a pH above pH 5such as a pH above pH 6, such as a pH above 7 such as a pH in the rangeof pH 5-10, such as a pH in the range of 6-9, such as a pH in the rangeof pH 6.5-8.5.

249. The method according to claims 226-248, wherein the dissolvedprecipitate is treated to further increase the purity of the PA.

250. The method according to claims 226-249, wherein the dissolvedprecipitate is clarified by centrifugation and/or filtration

251. The method according to claims 226-250, wherein the dissolvedprecipitate is added a soluble silicate and pH adjusted (if necessary)to achieve the precipitation of unwanted impurities.

252. The method according to claims 226-251, wherein the dissolvedprecipitate is added a divalent or trivalent metal ion and pH adjusted(if necessary) to achieve the precipitation of unwanted impurities.

253. The method according to claims 226-252, wherein the dissolvedprecipitate is treated with a solid phase adsorbent to adsorb unwantedimpurities.

254. The method according to claims 226-253, wherein the dissolvedprecipitate is treated with a solid phase adsorbent to adsorbglycoalkaloids and/or phenolic compounds.

255. The method according to claims 226-254, wherein the dissolvedprecipitate is subjected to a membrane filtration process to separate PAin the retentate from unwanted impurities in the permeate

256. The method according to claims 226-255, wherein the membranefiltration process is a tangential flow ultrafiltration processemploying a membrane having a nominal pore size in the range of approx.10.000-200.000 kDa, such as in the range of approx. 30.000-150.000 kDa,such as in the range of approx. 50.000-100.000 kDa

257. The method according to claims 226-256, wherein the isolation of PIin step d) above comprise subjecting the remaining aqueous phase to asolid phase adsorption step thereby adsorbing the PI and separating itfrom the aqueous phase.

258. The method according to claims 226-257, wherein the phaseadsorption is performed using an adsorbent having negatively chargedligands such as ion exchanging ligands including carboxylic acid,sulfonic acid and phosphonic acid ligands.

259. The method according to claims 226-258, wherein the solid phaseadsorption is performed using an adsorbent having aromatic acid ligandsattached thereto.

260. The method according to claims 226-259, wherein the solid phaseadsorbent comprises a benzoic acid, a carboxymethyl benzene, a benzenesulfonic acid or a (sulfomethyl) benzene ligand or derivatives hereof.

261. The method according to claims 226-260, wherein the isolation of PIin step d) above comprise subjecting the remaining aqueous phase to amembrane filtration process separating PI in the retentate from at leastone of lipid, glycoalkaloid and phenolic compounds in the permeate.

262. The method according to claims 226-261, wherein said membranefiltration process is a tangential flow ultrafiltration process.

263. The method according to claims 226-262, wherein saidultrafiltration process is performed using a membrane having a nominalpore size (cut-off value) of less than 50.000 D, such as less than30.000 D. In one embodiment, the membrane has a nominal pore size ofabout 10.000 D.

264. The method according to claims 226-263, wherein the ultrafiltrationprocess is performed at a pH value in the range of pH 1-6, such as pH1.5-5.0, such as pH 2.0-4.5, such as pH 2.5-4.0 such as pH 3.0-4.0, suchas pH 1.5-2.5.

265. The method according to claims 226-264, wherein the PI isolated instep d) contains less than 0.30 g PA per PI, such as less than 0.20 gPA, such as less than 0.15 g PA, such as less than 0.10 g PA per g PI.

266. The method according to claims 226-265, wherein the PI isolated instep d) contains less than 200 ppm solanine, such as less than 100 ppmsolanine such as less than 70 ppm solanine, such as less than 50 ppmsolanine, such as less than 25 ppm solanine, such as less than 10 ppmsolanine on a dry matter basis.

267. The method according to claims 226-266, wherein the PI isolated instep d) has a purity (N×6.25) corresponding to at least 70%, such as atleast 75%, such as at least 80%, such as at least 85%, such as at least90% PI on a dry matter basis.

268. The method according to claims 226-267, wherein the PI isolated instep d) constitutes more than 75%, such as more than 80%, such as morethan 85%, such as, more than 90%, such as more than 95% of the PIpresent in the aqueous phase of step a)

269. The method according to claims 226-268, wherein the PI isolated instep d) contains less than 25%, such as less than 15%, such as less than10%, such as less than 5%, such as less than 2% of the polyphenoloxidaseactivity present in the aqueous phase provided in step a) on a drymatter basis.

270. The method according to claims 226-269, wherein the ultrafiltrationprocess is performed at a pH value in the range of pH 0.1-1.0, such aspH 0.5-0.9,

271. The method according to claims 226-270, wherein the isolation of PIin step d) comprise subjecting the remaining aqueous phase to a solidphase adsorption step thereby adsorbing glycoalkaloids and phenoliccompounds and separating it from the aqueous phase.

272. The method according to claims 226-271, wherein the isolation of PIin step d) comprise subjecting the PI retentate after the ultrationprocess to a solid phase adsorption step thereby adsorbingglycoalkaloids and phenolic compounds and separating it from the PIretentate.

273. The method according to claim 272, wherein the solid phaseadsorption is performed by contacting the remaining aqueous phase or thePI retentate with a solid phase adsorbent selected from the group ofactivated carbon, layered silicate adsorbents and porous syntheticpolymers.

274. The method according to claim 273, wherein the porous syntheticpolymer is a hydrophobic adsorbent

275. The method according to claim 274, wherein the porous syntheticpolymer is a hydrophobic adsorbent comprising a cross-linked aromaticbackbone such as a cross-linked vinyl benzene backbone.

276. The method according to claim 275, wherein the porous syntheticpolymer is a Dowex, Lewatit or Amberlite adsorbent.

277. A method for isolating a first group of compounds selected from oneor more of patatin protein (PA), protease inhibitor protein (PI),lipoxygenase (LipO) and polyphenol oxidase (PPO) from a second group ofcompounds selected from one or more of PA, PI, LipO, PPO, pectin, lipid,glycoalkaloid and phenolic compounds said method comprising

a) providing an aqueous phase comprising compounds selected from two ormore of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid and phenoliccompounds of which at least one compound is selected from PA, PI, LipOand PPO;

b) performing one or more steps to reduce the concentration of solaninein the dry matter of the aqueous phase with at least 15 percent, and toachieve an optical density at 620 nm of the remaining aqueous phase ofless than 0.7;

c) contacting the remaining aqueous phase with a mobile solubilizedligand at physico-chemical conditions allowing formation of a complexbetween the ligand and the compounds selected from one or more of PA,PI, LipO and PPO;

d) allowing the complex to separate from the aqueous supernatant phase,optionally by changing said physico-chemical conditions in thecomposition to reduce the solubility of the complex; and

e) isolating the complex separated from the aqueous phase.

278. A method for isolating a first group of compounds selected from oneor more of patatin protein (PA), protease inhibitor protein (PI),lipoxygenase (LipO) and polyphenol oxidase (PPO) from a second group ofcompounds selected from one or more of PA, PI, LipO, PPO, pectin, lipid,glycoalkaloid and phenolic compounds said method comprising

a) providing an aqueous phase comprising compounds selected from two ormore of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid and phenoliccompounds of which at least one compound is selected from PA, PI, LipOand PPO;

b) performing one or more steps to reduce the concentration of solaninein the dry matter of the aqueous phase with at least 15 percent, toachieve an optical density at 620 nm of the remaining aqueous phase ofless than 0.7;

f) adjusting pH of the remaining aqueous phase (from step b)) to allowthe formation of a precipitate comprising PA; and

g) isolating the precipitate from the aqueous phase.

279. A method for isolating a first group of compounds selected from oneor more of patatin protein (PA), protease inhibitor protein (PI),lipoxygenase (LipO) and polyphenol oxidase (PPO) from a second group ofcompounds selected from one or more of PA, PI, LipO, PPO, pectin, lipid,glycoalkaloid and phenolic compounds said method comprising

a) providing an aqueous phase comprising compounds selected from two ormore of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid and phenoliccompounds of which at least one compound is selected from PA, PI, LipOand PPO;

b) performing one or more steps to reduce the concentration of solaninein the dry matter of the aqueous phase with at least 15 percent, toachieve an optical density at 620 nm of the remaining aqueous phase ofless than 0.7; and

h) subjecting the remaining aqueous phase (from step b)) to a membranefiltration process separating at least one of PA and PI in the retentatefrom at least one of PA, PI, LipO, PPO, pectin, lipid, glycoalkaloid andphenolic compounds in the permeate.

280. The method according to any one of claims 277-279, wherein theconcentration of solanine in the dry matter of the aqueous phase reducedwith at least 20%, such as at least 25%.

281. The method according to any one of claims 277-280, wherein theoptical density at 620 nm of the remaining aqueous phase of less thanless than 0.5. The optical density may be less than 0.3. The opticaldensity may be less than 0.2. The optical density may be less than 0.1.

282. The method according to any one of claims 277-281, wherein thereduction of the concentration of solanine in step b) can be done bychanging the physico-chemical conditions by any of the methods mentionedherein, including contacting the aqueous phase with soluble silicate.

283. The method according to any one of claims 277-282, wherein thereduction of the concentration of solanine (step b) and to achieving anoptical density at 620 nm of the remaining phase the result of two ormore independent steps.

284. The method according to any one of claims 277-283, wherein thereduction of the concentration of solanine (step b) and achieving anoptical density at 620 nm of the remaining phase is the result of asingle step.

285. The method according to any one of claims 277-284, wherein the oneor more steps needed to achieve the reduction of the concentration ofsolanine (step b) and achieving an optical density at 620 nm of theremaining phase can comprise any of the procedures for reducingturbidity mentioned herein, for example a combined step with treatmentusing silicate and calcium.

286. The method according to any one of claims 1-285, wherein step b)does not comprise the addition of an acrylic polymer.

The invention claimed is:
 1. A method for reducing turbidity of anaqueous phase comprising compounds selected from two or more of PA, PI,PPO, LipO, pectin, lipid, glycoalkaloid and phenolic compounds of whichat least one compound is selected from PA, PI, LipO and PPO, the methodcomprising: a) providing an aqueous phase comprising compounds selectedfrom two or more of PA, PI, PPO, LipO, pectin, lipid, glycoalkaloid andphenolic compounds of which at least one compound is selected from PA,PI, LipO and PPO; b) contacting the aqueous phase with a solublesilicate at a pH in the range of 3-10, allowing formation of aninsoluble precipitate comprising said silicate and one or more of thecompounds selected from LipO, PPO, pectin, lipid, glycoalkaloid andphenolic compounds, said insoluble precipitate being subsequentlyremoved from the aqueous phase by physical means; thereby obtaining anaqueous phase having reduced turbidity compared to an untreated aqueousphase.
 2. The method according to claim 1, wherein step b) does notcomprise the addition of a synthetic polymer.
 3. The method according toclaim 1, wherein step b) does not comprise the addition of an acrylicpolymer.
 4. The method according to claim 1, which method after step b)comprises the steps of; c) contacting the remaining aqueous phase with amobile solubilized ligand at physico-chemical conditions allowingformation of a complex between the ligand and the compounds selectedfrom one or more of PA, PI, LipO and PPO; d) allowing the complex toseparate from the aqueous supernatant phase, optionally by changing saidphysico-chemical conditions in the composition to reduce the solubilityof the complex; and e) isolating the complex separated from the aqueousphase.
 5. The method according to claim 1, which method after step b)comprises the steps of; f) adjusting pH of the remaining aqueous phase(from step b) to allow the formation of a precipitate comprising PA; g)isolating the precipitate from the aqueous phase.
 6. The methodaccording to claim 1, which method after step b) comprises the step of;h) subjecting the remaining aqueous phase (from step b) to a membranefiltration process separating at least one of PA and PI in the retentatefrom at least one of PA, PI, LipO, PPO, pectin, lipid, glycoalkaloid andphenolic compounds in the permeate.
 7. The method according to claim 1,wherein the silicate concentration is in the range of 0.2-5 g/L.
 8. Themethod according to claim 1, wherein silicate is sodium silicate.
 9. Themethod according to claim 1, wherein step b) further comprises additionof a divalent or trivalent metal ion at a concentration in the aqueousphase of between 2-100 mM.
 10. The method according to claim 9, whereinthe divalent or trivalent metal ion is a calcium, magnesium or aluminumion.
 11. The method according to claim 1, wherein the physical means instep b) is centrifugation and the supernatant is subsequently removed.12. The method according to claim 1, wherein the aqueous phase providedin step a) comprises the glycoalkaloid solanine and wherein step b)comprises performing one or more steps to reduce solanine concentrationin the dry matter of the aqueous phase with at least 15 percent, and toachieve an optical density at 620 nm of the remaining aqueous phase ofless than 0.7.
 13. The method according to claim 1, wherein the pH ofthe aqueous phase in step b) is adjusted to a pH in the range of 5-9.14. The method according to any of claim 1, wherein the formation of aninsoluble precipitate in step b) is made by incubating the aqueous phasefor less than 120 min.
 15. The method according to claim 1, wherein theformation of an insoluble precipitate in step b) is made by incubatingthe aqueous phase at 15-50° C.
 16. The method according to claim 1,wherein the aqueous phase is a root or tuber juice.
 17. The methodaccording to claim 16, wherein the juice is potato juice.
 18. A root ortuber juice, obtainable by a method according to claim 1, comprising atleast 0.5 wt. % of dissolved protein, wherein the protein is native andwherein the clarity, expressed as OD620, is less than 0.8.
 19. The rootor tuber juice according to claim 18, which does not comprise an acrylicpolymer.
 20. A method comprising adding the product obtainable by amethod according to claim 1 to a food, animal feed, pet food, beverage,cosmetic, pharmaceutical, nutraceutical, dietary supplement orfermentation broth.